#351

2026-05-23 07:21:15 +09:00 · 2026-05-23 03:50:54 +09:00 · 2026-05-22 03:29:18 +09:00
@@ -84,14 +84,12 @@ cd frontend
 npm run dev
 npm run build
 npm run lint
-npm run test
-npm run test:run
 npm run preview
 ```

 `npm run build` runs `tsc -b && vite build`, then `postbuild` runs `node scripts/generate-sitemap.js`.

-`npm run test` runs Vitest in watch mode. Use `npm run test:run` for a non-watch frontend test run.
+Do not write or report `npm test` as a repository command unless a `test` script is added to `frontend/package.json`.

 ## Coding style

@@ -124,49 +122,13 @@ npm run preview
 - Keep page-level code under `frontend/src/pages` and shared UI/feature code under `frontend/src/components` unless existing patterns point elsewhere.
 - Match existing Tailwind, component, and import alias conventions.

-### Frontend TSX style
-
- Preserve the local TSX formatting style. Do not normalize TSX to common Prettier-style React formatting unless explicitly asked.
- Prefer `const` arrow functions for TypeScript/TSX component and helper declarations.
- Put two blank lines before and after top-level `const` function declarations, unless imports, exports, or file boundaries make that awkward.
- In TSX, indent nested tag attributes with one tab relative to the tag line. With the project tab width, this visually appears as 4 spaces.
- Keep a tag's closing marker on the same line as the final prop when the tag spans multiple lines. Do not put `/>` or `>` on its own line unless the existing surrounding code does so.
- Keep JSX closing parentheses in the existing compact style, for example `</div>)` rather than moving `)` onto a separate line.
-
-Preferred:
-
-```tsx
-const PostFormTagsArea: FC<Props> = ({ tags, setTags, errors, ...rest }) => {
-  return (
-      <TextArea
-	  {...rest}
-	  ref={ref}
-	  value={tags}
-	  invalid={errors && errors.length > 0}
-	  onChange={ev => setTags (ev.target.value)}/>)
-}
-```
-
-Avoid:
-
-```tsx
-function PostFormTagsArea ({ tags, setTags }: Props) {
-  return (
-    <TextArea
-      value={tags}
-      onChange={ev => setTags (ev.target.value)}
-    />
-  )
-}
-```
-
 ## Codex workflow

 - First inspect existing patterns; do not invent new architecture when a local convention exists.
 - Keep changes scoped to the requested issue.
 - Do not scan or summarize dependency/generated/runtime directories such as `node_modules`, `dist`, `tmp`, `log`, and `storage` unless explicitly needed.
 - Before touching wiki, tag, versioning, BAN, IP BAN, or authentication behavior, inspect the related request specs and service objects.
- If frontend code changes, run the existing frontend verification commands that apply: `npm run build`, `npm run lint`, and `npm run test:run`.
+- If frontend code changes, run the existing frontend verification commands that apply: `npm run build` and `npm run lint`.
 - If backend code changes, run the relevant RSpec command; for broad backend changes, run `bundle exec rspec`.
 - If a verification command cannot be run or fails, report the exact command and failure.

@@ -69,5 +69,3 @@ gem 'discard'
 gem "rspec-rails", "~> 8.0", :groups => [:development, :test]

 gem 'aws-sdk-s3', require: false
-
-gem 'rails-i18n', '~> 8.0.0'
@@ -306,9 +306,6 @@ GEM
    rails-html-sanitizer (1.6.2)
      loofah (~> 2.21)
      nokogiri (>= 1.15.7, != 1.16.7, != 1.16.6, != 1.16.5, != 1.16.4, != 1.16.3, != 1.16.2, != 1.16.1, != 1.16.0.rc1, != 1.16.0)
-    rails-i18n (8.0.2)
-      i18n (>= 0.7, < 2)
-      railties (>= 8.0.0, < 9)
    railties (8.0.2)
      actionpack (= 8.0.2)
      activesupport (= 8.0.2)
@@ -480,7 +477,6 @@ DEPENDENCIES
  puma (>= 5.0)
  rack-cors
  rails (~> 8.0.2)
-  rails-i18n (~> 8.0.0)
  rspec-rails (~> 8.0)
  rubocop-rails-omakase
  sprockets-rails
@@ -1,7 +1,4 @@
 class ApplicationController < ActionController::API
-  rescue_from ActiveRecord::RecordInvalid, with: :render_record_invalid
-  rescue_from ActiveRecord::RecordNotUnique, with: :render_record_not_unique
-
  before_action :reject_banned_ip_address!
  before_action :authenticate_user
  before_action :reject_banned_user!
@@ -28,27 +25,6 @@ class ApplicationController < ActionController::API
    end
  end

-  def render_bad_request message = 'リクエストが不正です．'
-    render json: { type: 'bad_request',
-                   message:,
-                   errors: { },
-                   base_errors: [message] },
-           status: :bad_request
-  end
-
-  def render_unprocessable_entity message = '入力を確認してください．', field: nil
-    render_validation_error(fields: field ? { field => [message] } : { },
-                            base: field ? [] : [message])
-  end
-
-  def render_record_invalid error
-    render_validation_error error.record
-  end
-
-  def render_record_not_unique _error = nil
-    render_validation_error base: ['すでに存在してゐます．']
-  end
-
  def reject_banned_ip_address!
    ip_address = IpAddress.find_by(ip_address: IPAddr.new(request.remote_ip).hton)
    return unless ip_address&.banned?
@@ -61,28 +37,4 @@ class ApplicationController < ActionController::API

    head :forbidden
  end
-
-  def render_validation_error record = nil, fields: { }, base: [], status: :unprocessable_entity
-    errors = { }
-
-    if record
-      record.errors.each do |error|
-        errors[error.attribute] ||= []
-        errors[error.attribute] << error.message
-      end
-    end
-
-    fields.each do |attr, messages|
-      errors[attr.to_sym] ||= []
-      errors[attr.to_sym].concat(Array(messages))
-    end
-
-    base_errors = Array(base) + Array(errors.delete(:base))
-
-    render json: { type: 'validation_error',
-                   message: '入力内容を確認してください．',
-                   errors:,
-                   base_errors: },
-           status:
-  end
 end
@@ -2,8 +2,7 @@ class DeerjikistsController < ApplicationController
  def show
    platform = params[:platform].to_s.strip
    code = params[:code].to_s.strip
-    return render_bad_request('platform は必須です．') if platform.blank?
-    return render_bad_request('code は必須です．') if code.blank?
+    return head :bad_request if platform.blank? || code.blank?

    deerjikist = Deerjikist
                 .joins(:tag)
@@ -23,9 +22,7 @@ class DeerjikistsController < ApplicationController
    platform = params[:platform].to_s.strip
    code = params[:code].to_s.strip
    tag_id = params[:tag_id].to_i
-    return render_bad_request('platform は必須です．') if platform.blank?
-    return render_bad_request('code は必須です．') if code.blank?
-    return render_bad_request('tag_id が不正です．') if tag_id <= 0
+    return head :bad_request if platform.blank? || code.blank? || tag_id <= 0

    deerjikist = Deerjikist.find_or_initialize_by(platform:, code:).tap do |d|
      d.tag_id = tag_id
@@ -41,8 +38,7 @@ class DeerjikistsController < ApplicationController

    platform = params[:platform].to_s.strip
    code = params[:code].to_s.strip
-    return render_bad_request('platform は必須です．') if platform.blank?
-    return render_bad_request('code は必須です．') if code.blank?
+    return head :bad_request if platform.blank? || code.blank?

    Deerjikist.find([platform, code]).destroy!

@@ -40,11 +40,7 @@ class MaterialsController < ApplicationController
    tag_name_raw = params[:tag].to_s.strip
    file = params[:file]
    url = params[:url].to_s.strip.presence
-    return render_unprocessable_entity('タグは必須です．', field: :tag) if tag_name_raw.blank?
-    if file.blank? && url.blank?
-      return render_validation_error fields: { file: ['ファイルまたは URL は必須です．'],
-                                               url: ['ファイルまたは URL は必須です．'] }
-    end
+    return head :bad_request if tag_name_raw.blank? || (file.blank? && url.blank?)

    tag_name = TagName.find_undiscard_or_create_by!(name: tag_name_raw)
    tag = tag_name.tag
@@ -58,7 +54,7 @@ class MaterialsController < ApplicationController
    if material.save
      render json: MaterialRepr.base(material, host: request.base_url), status: :created
    else
-      render_validation_error material
+      render json: { errors: material.errors.full_messages }, status: :unprocessable_entity
    end
  end

@@ -72,11 +68,7 @@ class MaterialsController < ApplicationController
    tag_name_raw = params[:tag].to_s.strip
    file = params[:file]
    url = params[:url].to_s.strip.presence
-    return render_unprocessable_entity('タグは必須です．', field: :tag) if tag_name_raw.blank?
-    if file.blank? && url.blank?
-      return render_validation_error fields: { file: ['ファイルまたは URL は必須です．'],
-                                               url: ['ファイルまたは URL は必須です．'] }
-    end
+    return head :bad_request if tag_name_raw.blank? || (file.blank? && url.blank?)

    tag_name = TagName.find_undiscard_or_create_by!(name: tag_name_raw)
    tag = tag_name.tag
@@ -92,7 +84,7 @@ class MaterialsController < ApplicationController
    if material.save
      render json: MaterialRepr.base(material, host: request.base_url)
    else
-      render_validation_error material
+      render json: { errors: material.errors.full_messages }, status: :unprocessable_entity
    end
  end

@@ -1,69 +1,26 @@
 class NicoTagsController < ApplicationController
  def index
-    name = params[:name].presence
-    linked_tag = params[:linked_tag].presence
-    link_status = params[:link_status].presence
-    order = params[:order].to_s.split(':', 2).map(&:strip)
-    order[0] = 'updated_at' unless order[0].in?(['name', 'created_at', 'updated_at'])
-    unless order[1].in?(['asc', 'desc'])
-      order[1] = order[0] == 'name' ? 'asc' : 'desc'
-    end
-    page = (params[:page].presence || 1).to_i
-    limit = (params[:limit].presence || 20).to_i
-
-    page = 1 if page < 1
-    limit = 1 if limit < 1
-
-    post_tag_max_sql =
-        PostTag
-        .select('tag_id, MAX(created_at) AS max_created_at')
-        .group('tag_id')
-        .to_sql
+    limit = (params[:limit] || 20).to_i
+    cursor = params[:cursor].presence

    q = Tag.nico_tags
-           .joins(:tag_name)
-           .joins("LEFT JOIN (#{ post_tag_max_sql }) post_tag_max " \
-                  'ON post_tag_max.tag_id = tags.id')
           .includes(:tag_name, tag_name: :wiki_page, linked_tags: { tag_name: :wiki_page })
-    q = q.where('tag_names.name LIKE ?', "%#{ name }%") if name
-    if linked_tag
-      linked_tag_ids =
-        Tag
-        .joins(:tag_name)
-        .where('tag_names.name LIKE ?', "%#{ linked_tag }%")
-        .pluck(:id)
-      linked_nico_tag_ids = NicoTagRelation.where(tag_id: linked_tag_ids).pluck(:nico_tag_id)
-      q = q.where(id: linked_nico_tag_ids)
-    end
-    if link_status.in?(['linked', 'unlinked'])
-      exists_sql =
-          'EXISTS (SELECT 1 FROM nico_tag_relations ' \
-          'WHERE nico_tag_relations.nico_tag_id = tags.id)'
-      q = link_status == 'linked' ? q.where(exists_sql) : q.where("NOT #{ exists_sql }")
-    end
+           .order(updated_at: :desc)
+    q = q.where('tags.updated_at < ?', Time.iso8601(cursor)) if cursor

-    count = q.count
-    sort_sql =
-        case order[0]
-        when 'name'
-          'tag_names.name'
-        when 'updated_at'
-          'post_tag_max.max_created_at'
-        else
-          "tags.#{ order[0] }"
-        end
-    tags = q.reselect('tags.*',
-                      Arel.sql('post_tag_max.max_created_at AS recent_post_tag_created_at'))
-            .order(Arel.sql("#{ sort_sql } #{ order[1] }, tags.id #{ order[1] }"))
-            .limit(limit)
-            .offset((page - 1) * limit)
-            .to_a
+    tags = q.limit(limit + 1).to_a
+
+    next_cursor = nil
+    if tags.size > limit
+      next_cursor = tags.last.updated_at.iso8601(6)
+      tags = tags.first(limit)
+    end

    render json: { tags: tags.map { |tag|
-      TagRepr.base(tag).merge(
-          recent_post_tag_created_at: tag.recent_post_tag_created_at,
-          linked_tags: tag.linked_tags.map { |lt| TagRepr.base(lt) })
-    }, count: }
+      TagRepr.base(tag).merge(linked_tags: tag.linked_tags.map { |lt|
+        TagRepr.base(lt)
+      })
+    }, next_cursor: }
  end

  def update
@@ -73,18 +30,14 @@ class NicoTagsController < ApplicationController
    id = params[:id].to_i

    tag = Tag.find(id)
-    return render_bad_request('ニコニコ・タグを指定してください．') unless tag.nico?
+    return head :bad_request unless tag.nico?

    linked_tag_names = params[:tags].to_s.split
-    linked_tags = nil
+    linked_tags = Tag.normalise_tags!(linked_tag_names, with_tagme: false,
+                                                        with_no_deerjikist: false)
+    return head :bad_request if linked_tags.any? { |t| t.nico? }

    ApplicationRecord.transaction do
-      linked_tags = Tag.normalise_tags!(linked_tag_names, with_tagme: false,
-                                                          with_no_deerjikist: false)
-      if linked_tags.any? { |t| t.nico? }
-        raise Tag::NicoTagNormalisationError
-      end
-
      TagVersioning.record_tag_snapshots!(linked_tags, created_by_user: current_user)

      tag.linked_tags = linked_tags
@@ -94,21 +47,5 @@ class NicoTagsController < ApplicationController
    end

    render json: tag.linked_tags.map { |t| TagRepr.base(t) }, status: :ok
-  rescue Tag::NicoTagNormalisationError
-    render_validation_error fields: { tags: ['ニコニコ・タグ同士は連携できません．'] }
-  rescue ActiveRecord::RecordInvalid => e
-    render_nico_tag_form_record_invalid e.record
-  end
-
-  private
-
-  def render_nico_tag_form_record_invalid record
-    if record.is_a?(TagName) || record.is_a?(Tag)
-      render_validation_error fields: { tags: record.errors.full_messages.map { |message|
-        "タグ名 “#{ record.name }”: #{ message }"
-      } }
-    else
-      render_validation_error record
-    end
  end
 end
@@ -44,7 +44,7 @@ class PostsController < ApplicationController
        filtered_posts
        .joins("LEFT JOIN (#{ pt_max_sql }) pt_max ON pt_max.post_id = posts.id")
        .reselect('posts.*', Arel.sql("#{ updated_at_all_sql } AS updated_at_all"))
-        .preload(:uploaded_user, tags: [:deerjikists, :materials, { tag_name: :wiki_page }])
+        .preload(tags: [:deerjikists, :materials, { tag_name: :wiki_page }])
        .with_attached_thumbnail

    q = q.where('posts.url LIKE ?', "%#{ url }%") if url
@@ -95,35 +95,22 @@ class PostsController < ApplicationController
  end

  def random
-    post = filtered_posts.preload(:uploaded_user,
-                                  tags: [:deerjikists, :materials, { tag_name: :wiki_page }])
-                         .with_attached_thumbnail
-                         .order('RAND()')
-                         .first
+    post = filtered_posts
+           .preload(tags: [:deerjikists, :materials, { tag_name: :wiki_page }])
+           .order('RAND()')
+           .first
    return head :not_found unless post

    render json: PostRepr.base(post, current_user)
  end

  def show
-    post =
-        Post
-        .includes(:uploaded_user, tags: [:deerjikists, :materials, { tag_name: :wiki_page }])
-        .with_attached_thumbnail
-        .find_by(id: params[:id])
+    post = Post.includes(tags: [:deerjikists, :materials, { tag_name: :wiki_page }]).find_by(id: params[:id])
    return head :not_found unless post

-    parent_posts = post.parents.with_attached_thumbnail.order(:id).to_a
-    child_posts = post.children.with_attached_thumbnail.order(:id).to_a
-    sibling_posts = sibling_posts_by_parent(parent_posts.map(&:id))
-    related = post.related(limit: 20).to_a
-
-    render json: PostRepr.detail(post, current_user,
-                                 parent_posts:,
-                                 child_posts:,
-                                 sibling_posts:,
-                                 related:)
-                         .merge(tags: build_tag_tree_for(post.tags))
+    render json: PostRepr.base(post, current_user)
+                         .merge(tags: build_tag_tree_for(post),
+                                related: PostRepr.many(post.related(limit: 20)))
  end

  def create
@@ -146,11 +133,11 @@ class PostsController < ApplicationController
    ApplicationRecord.transaction do
      post.save!

-      tags = Tag.normalise_tags!(tag_names)
+      Tag.normalise_tags!(tag_names, with_sections: true) => { tags:, sections: }
      TagVersioning.record_tag_snapshots!(tags, created_by_user: current_user)

      tags = Tag.expand_parent_tags(tags)
-      sync_post_tags!(post, tags)
+      sync_post_tags!(post, tags, sections)

      sync_parent_posts!(post, parent_post_ids)

@@ -162,11 +149,11 @@ class PostsController < ApplicationController
    post.reload
    render json: PostRepr.base(post), status: :created
  rescue Tag::NicoTagNormalisationError
-    render_validation_error fields: { tags: 'ニコニコ・タグは直接指定できません．' }
+    head :bad_request
  rescue ArgumentError => e
-    render_validation_error fields: { parent_post_ids: [e.message] }
+    render json: { errors: [e.message] }, status: :unprocessable_entity
  rescue ActiveRecord::RecordInvalid => e
-    render_post_form_record_invalid e.record
+    render json: { errors: e.record.errors.full_messages }, status: :unprocessable_entity
  end

  def viewed
@@ -189,10 +176,10 @@ class PostsController < ApplicationController

    force = bool?(:force)
    merge = bool?(:merge)
-    return render_bad_request('force と merge は同時に指定できません．') if force && merge
+    return head :bad_request if force && merge

    base_version_no = parse_base_version_no
-    return render_bad_request('base_version_no は必須です．') if !(force) && !(base_version_no)
+    return head :bad_request if !(force) && !(base_version_no)

    title = params[:title].presence
    tag_names = params[:tags].to_s.split
@@ -249,14 +236,14 @@ class PostsController < ApplicationController

    post.reload
    json = PostRepr.base(post, current_user)
-    json['tags'] = build_tag_tree_for(post.tags)
+    json['tags'] = build_tag_tree_for(post)
    render json:, status: :ok
  rescue Tag::NicoTagNormalisationError
-    render_validation_error fields: { tags: ['ニコニコ・タグは直接指定できません．'] }
+    head :bad_request
  rescue ArgumentError => e
-    render_validation_error fields: { parent_post_ids: [e.message] }
+    render json: { errors: [e.message] }, status: :unprocessable_entity
  rescue ActiveRecord::RecordInvalid => e
-    render_post_form_record_invalid e.record
+    render json: { errors: e.record.errors.full_messages }, status: :unprocessable_entity
  end

  def changes
@@ -351,7 +338,7 @@ class PostsController < ApplicationController
  def tagged_post_ids_for(name) =
      Post.joins(tags: :tag_name).where(tag_names: { name: }).select(:id)

-  def sync_post_tags! post, desired_tags
+  def sync_post_tags! post, desired_tags, sections
    desired_tags.each do |t|
      t.save! if t.new_record?
    end
@@ -370,13 +357,20 @@ class PostsController < ApplicationController
      end
    end

+    PostTagSection.where(post_id: post.id).destroy_all
+    sections.each do |tag_id, ranges|
+      ranges.each do |begin_ms, end_ms|
+        PostTagSection.create!(post_id: post.id, tag_id:, begin_ms:, end_ms:)
+      end
+    end
+
    PostTag.where(post_id: post.id, tag_id: to_remove.to_a).kept.find_each do |pt|
      pt.discard_by!(current_user)
    end
  end

-  def build_tag_tree_for tags
-    tags = tags.to_a
+  def build_tag_tree_for post
+    tags = post.tags.to_a
    tag_ids = tags.map(&:id)

    implications = TagImplication.where(parent_tag_id: tag_ids, tag_id: tag_ids)
@@ -398,8 +392,11 @@ class PostsController < ApplicationController
      tag = tags_by_id[tag_id]
      return nil unless tag

+      sections = PostTagSection.where(post_id: post.id, tag_id:)
+                 .as_json(only: [:begin_ms, :end_ms])
+
      if path.include?(tag_id)
-        return TagRepr.inline(tag).merge(children: [])
+        return TagRepr.base(tag).merge(children: [], sections:)
      end

      if memo.key?(tag_id)
@@ -411,32 +408,18 @@ class PostsController < ApplicationController

      children = child_ids.filter_map { |cid| build_node.(cid, new_path) }

-      memo[tag_id] = TagRepr.inline(tag).merge(children:)
+      memo[tag_id] = TagRepr.base(tag).merge(children:, sections:)
    end

    root_ids.filter_map { |id| build_node.call(id, []) }
  end

-  def sibling_posts_by_parent parent_post_ids
-    return { } if parent_post_ids.blank?
-
-    implications =
-        PostImplication
-        .where(parent_post_id: parent_post_ids)
-        .includes(post: { thumbnail_attachment: :blob })
-        .order(:parent_post_id, :post_id)
-
-    implications.group_by(&:parent_post_id).transform_values { |items|
-      items.map(&:post)
-    }
-  end
-
  def parse_parent_post_ids
    raise ArgumentError, 'parent_post_ids は必須です．' unless params.key?(:parent_post_ids)

    params[:parent_post_ids].to_s.split.map { |token|
      id = Integer(token, exception: false)
-      raise ArgumentError, "親投稿 Id. が不正です: #{ token }" if id.nil? || id <= 0
+      raise ArgumentError, "親投稿 Id. が不正です: #{ token }" if !(id) || id <= 0

      id
    }.uniq
@@ -444,7 +427,7 @@ class PostsController < ApplicationController

  def sync_parent_posts! post, parent_post_ids
    if parent_post_ids.include?(post.id)
-      post.errors.add :parent_post_ids, '自分自身を親投稿にはできません．'
+      post.errors.add(:base, '自分自身を親投稿にはできません．')
      raise ActiveRecord::RecordInvalid, post
    end

@@ -452,8 +435,7 @@ class PostsController < ApplicationController
    missing_ids = parent_post_ids - existing_ids

    if missing_ids.present?
-      post.errors.add :parent_post_ids,
-                      "存在しない親投稿 Id. があります: #{ missing_ids.join(' ') }"
+      post.errors.add(:base, "存在しない親投稿 ID があります: #{ missing_ids.join(' ') }")
      raise ActiveRecord::RecordInvalid, post
    end

@@ -499,7 +481,21 @@ class PostsController < ApplicationController
  end

  def editable_tag_names_from_post post
-    post.tags.not_nico.joins(:tag_name).order('tag_names.name').pluck('tag_names.name')
+    post
+        .post_tags
+        .kept
+        .joins(tag: :tag_name)
+        .merge(Tag.not_nico)
+        .includes(:sections, tag: :tag_name)
+        .order('tag_names.name')
+        .map do |post_tag|
+      name = post_tag.tag.tag_name.name
+      sections = post_tag.sections.sort_by(&:begin_ms)
+
+      next name if sections.empty?
+
+      "#{ name }#{ sections.map { Post.section_literal(_1) }.join }"
+    end
  end

  def post_incoming_snapshot title:, original_created_from:, original_created_before:,
@@ -531,9 +527,16 @@ class PostsController < ApplicationController
  end

  def incoming_tag_names_for_snapshot raw_tag_names
-    tags = Tag.normalise_tags!(raw_tag_names, with_tagme: false)
+    Tag.normalise_tags!(raw_tag_names, with_tagme: false, with_sections: true) =>
+        { tags:, sections: }

-    Tag.expand_parent_tags(tags).map(&:name).uniq.sort
+    Tag.expand_parent_tags(tags).uniq(&:id).map { |tag|
+      "#{ tag.name }#{ sections[tag.id].to_a.map { section_literal(_1) }.join }"
+    }.sort
+  end
+
+  def section_literal section
+    "[#{ Post.ms_to_time(section[0]) }-#{ Post.ms_to_time(section[1]) }]"
  end

  def post_conflict_json post:, base_version_no:, base_snapshot:,
@@ -620,7 +623,8 @@ class PostsController < ApplicationController
                 original_created_from: snapshot[:original_created_from],
                 original_created_before: snapshot[:original_created_before])

-    editable_tags = Tag.normalise_tags!(snapshot[:tag_names], with_tagme: false)
+    Tag.normalise_tags!(snapshot[:tag_names], with_tagme: false, with_sections: true) =>
+        { tags: editable_tags, sections: }
    TagVersioning.record_tag_snapshots!(editable_tags, created_by_user: current_user)

    readonly_tags = post.tags.nico.to_a
@@ -628,7 +632,7 @@ class PostsController < ApplicationController
    tags = readonly_tags + editable_tags
    tags = Tag.expand_parent_tags(tags)

-    sync_post_tags!(post, tags)
+    sync_post_tags!(post, tags, sections)
    sync_parent_posts!(post, snapshot[:parent_post_ids])

    PostVersionRecorder.record!(post:, event_type: :update, created_by_user: current_user)
@@ -669,14 +673,4 @@ class PostsController < ApplicationController

    merged.uniq.sort
  end
-
-  def render_post_form_record_invalid record
-    if record.is_a?(TagName) || record.is_a?(Tag)
-      render_validation_error fields: { tags: record.errors.full_messages.map { |message|
-        "タグ名 “#{ record.name }”: #{ message }"
-      } }
-    else
-      render_validation_error record
-    end
-  end
 end
@@ -4,7 +4,7 @@ class PreviewController < ApplicationController
    return head :unauthorized unless current_user

    url = params[:url]
-    return render_bad_request('URL は必須です．') unless url.present?
+    return head :bad_request unless url.present?

    unless url.start_with?(/http(s)?:\/\//)
      url = 'http://' + url
@@ -16,7 +16,7 @@ class PreviewController < ApplicationController

    render json: { title: title }
  rescue => e
-    render_bad_request(e.message)
+    render json: { error: e.message }, status: :bad_request
  end

  def thumbnail
@@ -25,7 +25,7 @@ class PreviewController < ApplicationController
    return head :unauthorized unless current_user

    url = params[:url]
-    return render_bad_request('URL は必須です．') if url.blank?
+    return head :bad_request if url.blank?

    unless url.start_with?(/http(s)?:\/\//)
      url = 'http://' + url
@@ -40,11 +40,7 @@ class PreviewController < ApplicationController
      File.delete(path) rescue nil
      send_file image.path, type: 'image/png', disposition: 'inline'
    else
-      render json: { type: 'internal_server_error',
-                     message: 'サムネールを生成できませんでした．',
-                     errors: { },
-                     base_errors: ['サムネールを生成できませんでした．'] },
-             status: :internal_server_error
+      render json: { error: 'Failed to generate thumbnail' }, status: :internal_server_error
    end
  end
 end
@@ -5,12 +5,11 @@ class TagChildrenController < ApplicationController

    parent_id = params[:parent_id]
    child_id = params[:child_id]
-    return render_bad_request('parent_id は必須です．') if parent_id.blank?
-    return render_bad_request('child_id は必須です．') if child_id.blank?
+    return head :bad_request if parent_id.blank? || child_id.blank?

    parent = Tag.find(parent_id)
    child = Tag.find(child_id)
-    return render_bad_request('ニコニコ・タグの階層は変更できません．') if parent.nico? || child.nico?
+    return head :bad_request if parent.nico? || child.nico?

    ApplicationRecord.transaction do
      TagVersioning.ensure_snapshot!(child, created_by_user: current_user)
@@ -28,12 +27,11 @@ class TagChildrenController < ApplicationController

    parent_id = params[:parent_id]
    child_id = params[:child_id]
-    return render_bad_request('parent_id は必須です．') if parent_id.blank?
-    return render_bad_request('child_id は必須です．') if child_id.blank?
+    return head :bad_request if parent_id.blank? || child_id.blank?

    parent = Tag.find(parent_id)
    child = Tag.find(child_id)
-    return render_bad_request('ニコニコ・タグの階層は変更できません．') if parent.nico? || child.nico?
+    return head :bad_request if parent.nico? || child.nico?

    ApplicationRecord.transaction do
      TagVersioning.ensure_snapshot!(child, created_by_user: current_user)
@@ -168,7 +168,7 @@ class TagsController < ApplicationController

  def show_by_name
    name = params[:name].to_s.strip
-    return render_bad_request('name は必須です．') if name.blank?
+    return head :bad_request if name.blank?

    tag = Tag.joins(:tag_name)
             .includes(:tag_name, :materials, tag_name: :wiki_page)
@@ -192,7 +192,7 @@ class TagsController < ApplicationController

  def deerjikists_by_name
    name = params[:name].to_s.strip
-    return render_bad_request('name は必須です．') if name.blank?
+    return head :bad_request if name.blank?

    tag = Tag.joins(:tag_name)
             .includes(:tag_name, tag_name: :wiki_page)
@@ -214,24 +214,21 @@ class TagsController < ApplicationController

    ApplicationRecord.transaction do
      tag.deerjikists = []
-      params[:_json].each.with_index do |item, i|
-        platform = item[:platform]
-        code = normalise_deerjikist_code(platform, item[:code])
+      params[:_json].each do
+        platform = _1[:platform]
+        code = normalise_deerjikist_code(platform, _1[:code])
        deerjikist = Deerjikist.find_or_initialize_by(platform:, code:)
        deerjikist.tag = tag
-        render_deerjikist_form_record_invalid(deerjikist, i) unless deerjikist.save
-        raise ActiveRecord::Rollback if performed?
+        deerjikist.save!
      end
    end

-    return if performed?
-
    render json: DeerjikistRepr.many(tag.reload.deerjikists)
  end

  def materials_by_name
    name = params[:name].to_s.strip
-    return render_bad_request('name は必須です．') if name.blank?
+    return head :bad_request if name.blank?

    tag = Tag.joins(:tag_name)
             .includes(:tag_name, :materials, tag_name: :wiki_page)
@@ -250,16 +247,17 @@ class TagsController < ApplicationController

    name = params[:name].to_s.strip
    category = params[:category].to_s.strip
-    return render_unprocessable_entity('名前は必須です．', field: :name) if name.blank?
-    return render_unprocessable_entity('カテゴリは必須です．', field: :category) if category.blank?
+    return head :unprocessable_entity if name.blank? || category.blank?

    if name != tag.name &&
        tag.in?([Tag.tagme, Tag.bot, Tag.no_deerjikist, Tag.video, Tag.niconico])
-      return render_unprocessable_entity('システム・タグの名称は変更できません．', field: :name)
+      return render json: { error: 'システム・タグの名称は変更できません．' },
+                    status: :unprocessable_entity
    end

    if tag.nico? || category == 'nico'
-      return render_unprocessable_entity('ニコタグは変更できません．', field: :category)
+      return render json: { error: 'ニコタグは変更できません．' },
+                    status: :unprocessable_entity
    end

    alias_names = params[:aliases].to_s.split.uniq
@@ -304,7 +302,8 @@ class TagsController < ApplicationController
    tag = Tag.find(params[:id])

    if tag.nico? || (category.present? && category == 'nico')
-      return render_unprocessable_entity('ニコタグは変更できません．', field: :category)
+      return render json: { error: 'ニコタグは変更できません．' },
+                    status: :unprocessable_entity
    end

    ApplicationRecord.transaction do
@@ -438,23 +437,4 @@ class TagsController < ApplicationController
  rescue
    nil
  end
-
-  def render_deerjikist_form_record_invalid deerjikist, index
-    fields = { }
-
-    deerjikist.errors.each do |error|
-      field =
-          case error.attribute
-          when :platform, :code
-            "deerjikists.#{ index }.#{ error.attribute }"
-          else
-            :deerjikists
-          end
-
-      fields[field] ||= []
-      fields[field] << error.full_message
-    end
-
-    render_validation_error fields:
-  end
 end
@@ -15,7 +15,7 @@ class TheatreCommentsController < ApplicationController
    return head :unauthorized unless current_user

    content = params[:content]
-    return render_unprocessable_entity('本文は必須です．', field: :content) if content.blank?
+    return head :unprocessable_entity if content.blank?

    theatre = Theatre.find_by(id: params[:theatre_id])
    return head :not_found unless theatre
@@ -42,12 +42,12 @@ class UsersController < ApplicationController
    return head :unauthorized if user&.id != params[:id].to_i

    name = params[:name]
-    return render_unprocessable_entity('名前は必須です．', field: :name) if name.blank?
+    return head :bad_request if name.blank?

    if user.update(name:)
      render json: user.slice(:id, :name, :inheritance_code, :role), status: :ok
    else
-      render_validation_error user
+      render json: user.errors, status: :unprocessable_entity
    end
  end

@@ -46,7 +46,7 @@ class WikiPagesController < ApplicationController

  def diff
    id = params[:id]
-    return render_bad_request('id は必須です．') if id.blank?
+    return head :bad_request if id.blank?

    from = params[:from].presence
    to = params[:to].presence
@@ -56,7 +56,7 @@ class WikiPagesController < ApplicationController
    from_rev = from && page.wiki_revisions.find(from)
    to_rev = to ? page.wiki_revisions.find(to) : page.current_revision
    if ((from_rev && !(from_rev.content?)) || !(to_rev&.content?))
-      return render_unprocessable_entity('差分を表示できない版です．')
+      return head :unprocessable_entity
    end

    diffs = Diff::LCS.sdiff(from_rev&.body&.lines || [], to_rev.body.lines)
@@ -89,8 +89,7 @@ class WikiPagesController < ApplicationController
    body = params[:body].to_s
    message = params[:message].presence

-    return render_unprocessable_entity('タイトルは必須です．', field: :title) if title.blank?
-    return render_unprocessable_entity('本文は必須です．', field: :body) if body.blank?
+    return head :unprocessable_entity if title.blank? || body.blank?

    tag_name = TagName.find_undiscard_or_create_by!(name: title)

@@ -102,10 +101,8 @@ class WikiPagesController < ApplicationController
            message:)

    render json: WikiPageRepr.base(page), status: :created
-  rescue ActiveRecord::RecordInvalid => e
-    render_validation_error e.record
-  rescue ActiveRecord::RecordNotUnique
-    render_record_not_unique
+  rescue ActiveRecord::RecordInvalid, ActiveRecord::RecordNotUnique
+    head :unprocessable_entity
  end

  def update
@@ -115,8 +112,7 @@ class WikiPagesController < ApplicationController
    title = params[:title]&.strip
    body = params[:body].to_s

-    return render_unprocessable_entity('タイトルは必須です．', field: :title) if title.blank?
-    return render_unprocessable_entity('本文は必須です．', field: :body) if body.blank?
+    return head :unprocessable_entity if title.blank? || body.blank?

    page = WikiPage.find(params[:id])
    base_revision_id = params[:base_revision_id].presence
@@ -56,7 +56,38 @@ class Post < ApplicationRecord
    super(options).merge(thumbnail: nil)
  end

-  def snapshot_tag_names = tags.joins(:tag_name).order('tag_names.name').pluck('tag_names.name')
+  def snapshot_tag_names
+    post_tags
+        .kept
+        .joins(tag: :tag_name)
+        .includes(:sections, tag: :tag_name)
+        .order('tag_names.name')
+        .map do |post_tag|
+      name = post_tag.tag.tag_name.name
+      sections = post_tag.sections.sort_by(&:begin_ms)
+
+      next name if sections.empty?
+
+      "#{ name }#{ sections.map { Post.section_literal(_1) }.join }"
+    end
+  end
+
+  def self.section_literal section
+    "[#{ Post.ms_to_time(section.begin_ms) }-#{ Post.ms_to_time(section.end_ms) }]"
+  end
+
+  def self.ms_to_time ms
+    total_s = ms / 1_000
+    s = total_s % 60
+    min = (total_s / 60) % 60
+    h = total_s / 3_600
+
+    if h.positive?
+      '%d:%02d:%02d' % [h, min, s]
+    else
+      '%d:%02d' % [min, s]
+    end
+  end

  def snapshot_parent_post_ids = parents.order(:id).pluck(:id)

@@ -94,7 +125,7 @@ class Post < ApplicationRecord
    return if !(f) || !(b)

    if f >= b
-      errors.add :original_created_at, 'オリジナルの作成日時の順番がをかしぃです．'
+      errors.add :original_created_before, 'オリジナルの作成日時の順番がをかしぃです．'
    end
  end

@@ -10,6 +10,12 @@ class PostTag < ApplicationRecord
  belongs_to :created_user, class_name: 'User', optional: true
  belongs_to :deleted_user, class_name: 'User', optional: true

+  has_many :sections, -> { order(:begin_ms) }, class_name: 'PostTagSection',
+                                               foreign_key: [:post_id, :tag_id],
+                                               primary_key: [:post_id, :tag_id],
+                                               dependent: :delete_all,
+                                               inverse_of: :post_tag
+
  validates :post_id, presence: true
  validates :tag_id, presence: true
  validates :post_id, uniqueness: {
@@ -0,0 +1,20 @@
+class PostTagSection < ApplicationRecord
+  self.primary_key = :post_id, :tag_id, :begin_ms
+
+  belongs_to :post
+  belongs_to :tag
+
+  belongs_to :post_tag, -> { kept }, foreign_key: [:post_id, :tag_id],
+                                     primary_key: [:post_id, :tag_id],
+                                     inverse_of: :sections,
+                                     optional: true
+
+  validates :post_id, presence: true
+  validates :tag_id, presence: true
+
+  validates :begin_ms, presence: true,
+                       numericality: { only_integer: true, greater_than_or_equal_to: 0 }
+
+  validates :end_ms, presence: true,
+                     numericality: { only_integer: true, greater_than: :begin_ms }
+end
@@ -92,22 +92,50 @@ class Tag < ApplicationRecord

  def self.normalise_tags! tag_names, with_tagme: true,
                                      with_no_deerjikist: true,
-                                      deny_nico: true
+                                      deny_nico: true,
+                                      with_sections: false
    if deny_nico && tag_names.any? { |n| n.downcase.start_with?('nico:') }
      raise NicoTagNormalisationError
    end

+    sections = { }
    tags = tag_names.map do |name|
      pf, cat = CATEGORY_PREFIXES.find { |p, _| name.downcase.start_with?(p) } || ['', nil]
-      name = TagName.canonicalise(name.sub(/\A#{ pf }/i, '')).first
+
+      name = name.sub(/\A#{ pf }/i, '')
+
+      sections_by_tag = []
+      while n = name.sub!(/^(\S*?)\[([0-9:.]*?)-([0-9:.]*?)\](\S*?)$/, '\1\4 \2 \3')
+        name, *section_raw = n.split
+
+        begin_ms, end_ms = section_raw.map { time_to_ms(_1) }
+        next if begin_ms == end_ms
+
+        begin_ms, end_ms = end_ms, begin_ms if begin_ms > end_ms
+
+        sections_by_tag << [begin_ms, end_ms]
+      end
+
+      name = TagName.canonicalise(name).first
+
      find_or_create_by_tag_name!(name, category: (cat || :general)).tap do |tag|
        tag.update!(category: cat) if cat && tag.category != cat
+        next if sections_by_tag.empty?
+
+        sections[tag.id] ||= []
+        sections[tag.id].concat(sections_by_tag)
      end
    end

    tags << Tag.tagme if with_tagme && tags.size < 10 && tags.none?(Tag.tagme)
    tags << Tag.no_deerjikist if with_no_deerjikist && tags.all? { |t| !(t.deerjikist?) }
-    tags.uniq(&:id)
+    tags.uniq!(&:id)
+
+    if with_sections
+      { tags:, sections: }
+    else
+      tags
+    end
  end

  def self.expand_parent_tags tags
@@ -228,4 +256,23 @@ class Tag < ApplicationRecord
      errors.add :category, 'ニジラーと紐づいてゐるタグはニジラー・カテゴリである必要があります．'
    end
  end
+
+  def self.time_to_ms str
+    parts = str.split(':')
+
+    s_part = parts.pop
+    s, ms = s_part.split('.')
+
+    total_s = s.to_i
+
+    if parts.length >= 1
+      total_s += parts.pop.to_i * 60
+    end
+
+    if parts.length >= 1
+      total_s += parts.pop.to_i * 3_600
+    end
+
+    total_s * 1_000 + ms.to_s.ljust(3, '0')[0, 3].to_i
+  end
 end
@@ -2,65 +2,20 @@


 module PostRepr
-  BASE_FIELDS = [
-      :id,
-      :version_no,
-      :url,
-      :title,
-      :thumbnail_base,
-      :original_created_from,
-      :original_created_before,
-      :created_at,
-      :updated_at
-  ].freeze
+  BASE = { include: { tags: TagRepr::BASE, uploaded_user: UserRepr::BASE },
+           methods: [:parent_posts, :child_posts, :sibling_posts] }.freeze

  module_function

  def base post, current_user = nil
-    json = common(post)
-    json['tags'] = tag_json(post.tags)
-    json['uploaded_user'] = post.uploaded_user && UserRepr.base(post.uploaded_user)
-    json['viewed'] = current_user ? current_user.viewed?(post) : false
-    json
-  end
+    json = post.as_json(BASE)
+    return json.merge(viewed: false) unless current_user

-  def detail post, current_user = nil, parent_posts: [], child_posts: [],
-             sibling_posts: { }, related: []
-    base(post, current_user).merge(
-        'parent_posts' => cards(parent_posts),
-        'child_posts' => cards(child_posts),
-        'sibling_posts' => sibling_posts.transform_keys(&:to_s).transform_values { |posts|
-          cards(posts)
-        },
-        'related' => cards(related))
-  end
-
-  def card post
-    common(post).merge('parent_posts' => [], 'child_posts' => [])
-  end
-
-  def cards posts
-    posts.map { |post| card(post) }
+    viewed = current_user.viewed?(post)
+    json.merge(viewed:)
  end

  def many posts, current_user = nil
    posts.map { |p| base(p, current_user) }
  end
-
-  def common post
-    BASE_FIELDS.to_h { |field| [field.to_s, post.public_send(field)] }
-               .merge('thumbnail' => thumbnail_url(post))
-  end
-
-  def tag_json tags
-    tags.map { |tag| TagRepr.inline(tag) }
-  end
-
-  def thumbnail_url post
-    return nil unless post.thumbnail.attached?
-
-    Rails.application.routes.url_helpers.rails_blob_url(post.thumbnail, only_path: false)
-  rescue
-    nil
-  end
 end
@@ -12,9 +12,5 @@ module TagRepr
                            parents: tag.parents.map { _1.as_json(BASE) })
  end

-  def inline tag
-    tag.as_json(BASE).merge(aliases: [], parents: [])
-  end
-
  def many(tags) = tags.map { |t| base(t) }
 end
@@ -0,0 +1,19 @@
+class CreatePostTagSections < ActiveRecord::Migration[8.0]
+  def change
+    create_table :post_tag_sections, primary_key: [:post_id, :tag_id, :begin_ms] do |t|
+      t.references :post, null: false, foreign_key: true, index: false
+      t.references :tag, null: false, foreign_key: true, index: false
+      t.integer :begin_ms, null: false
+      t.integer :end_ms, null: false
+      t.timestamps
+
+      t.index [:post_id, :begin_ms], name: 'idx_post_tag_sections_post_id_begin_ms'
+
+      t.check_constraint 'begin_ms >= 0',
+                         name: 'chk_post_tag_sections_begin_ms_natural'
+
+      t.check_constraint 'begin_ms < end_ms',
+                         name: 'chk_post_tag_sections_end_ms_after_begin_ms'
+    end
+  end
+end
@@ -0,0 +1,9 @@
+class AddVideoMsToPosts < ActiveRecord::Migration[8.0]
+  def change
+    add_column :posts, :video_ms, :integer
+    add_index :posts, [:video_ms, :id], name: 'idx_posts_video_ms_id'
+
+    add_check_constraint :posts, 'video_ms IS NULL OR video_ms > 0',
+                         name: 'chk_posts_video_ms_positive'
+  end
+end
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.

-ActiveRecord::Schema[8.0].define(version: 2026_05_07_213300) do
+ActiveRecord::Schema[8.0].define(version: 2026_05_19_013100) do
  create_table "active_storage_attachments", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
    t.string "name", null: false
    t.string "record_type", null: false
@@ -137,6 +137,19 @@ ActiveRecord::Schema[8.0].define(version: 2026_05_07_213300) do
    t.index ["target_post_id"], name: "index_post_similarities_on_target_post_id"
  end

+  create_table "post_tag_sections", primary_key: ["post_id", "tag_id", "begin_ms"], charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
+    t.bigint "post_id", null: false
+    t.bigint "tag_id", null: false
+    t.integer "begin_ms", null: false
+    t.integer "end_ms", null: false
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["post_id", "begin_ms"], name: "idx_post_tag_sections_post_id_begin_ms"
+    t.index ["tag_id"], name: "fk_rails_8be3847903"
+    t.check_constraint "`begin_ms` < `end_ms`", name: "chk_post_tag_sections_end_ms_after_begin_ms"
+    t.check_constraint "`begin_ms` >= 0", name: "chk_post_tag_sections_begin_ms_natural"
+  end
+
  create_table "post_tags", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
    t.bigint "post_id", null: false
    t.bigint "tag_id", null: false
@@ -187,8 +200,11 @@ ActiveRecord::Schema[8.0].define(version: 2026_05_07_213300) do
    t.datetime "original_created_before"
    t.datetime "updated_at", null: false
    t.integer "version_no", null: false
+    t.integer "video_ms"
    t.index ["uploaded_user_id"], name: "index_posts_on_uploaded_user_id"
    t.index ["url"], name: "index_posts_on_url", unique: true
+    t.index ["video_ms", "id"], name: "idx_posts_video_ms_id"
+    t.check_constraint "(`video_ms` is null) or (`video_ms` > 0)", name: "chk_posts_video_ms_positive"
    t.check_constraint "`version_no` > 0", name: "chk_posts_version_no_positive"
  end

@@ -290,6 +306,7 @@ ActiveRecord::Schema[8.0].define(version: 2026_05_07_213300) do
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.index ["expires_at"], name: "index_theatre_watching_users_on_expires_at"
+    t.index ["theatre_id", "expires_at"], name: "idx_on_theatre_id_skip_expires_at_4c8de1dd42"
    t.index ["theatre_id", "expires_at"], name: "index_theatre_watching_users_on_theatre_id_and_expires_at"
    t.index ["theatre_id"], name: "index_theatre_watching_users_on_theatre_id"
    t.index ["user_id"], name: "index_theatre_watching_users_on_user_id"
@@ -446,6 +463,8 @@ ActiveRecord::Schema[8.0].define(version: 2026_05_07_213300) do
  add_foreign_key "post_implications", "posts", column: "parent_post_id"
  add_foreign_key "post_similarities", "posts"
  add_foreign_key "post_similarities", "posts", column: "target_post_id"
+  add_foreign_key "post_tag_sections", "posts"
+  add_foreign_key "post_tag_sections", "tags"
  add_foreign_key "post_tags", "posts"
  add_foreign_key "post_tags", "tags"
  add_foreign_key "post_tags", "users", column: "created_user_id"
@@ -0,0 +1,8 @@
+FactoryBot.define do
+  factory :post_tag_section do
+    association :post
+    association :tag
+    begin_ms { 1_000 }
+    end_ms { 2_000 }
+  end
+end
@@ -0,0 +1,6 @@
+FactoryBot.define do
+  factory :post_tag do
+    association :post
+    association :tag
+  end
+end
@@ -0,0 +1,8 @@
+FactoryBot.define do
+  factory :post do
+    sequence(:url) { |n| "https://example.com/factory-post-#{ n }" }
+    title { 'factory post' }
+    thumbnail_base { nil }
+    uploaded_user { nil }
+  end
+end
@@ -0,0 +1,29 @@
+RSpec.describe PostTag, type: :model do
+  describe '#sections' do
+    it 'loads sections by post_id and tag_id' do
+      post_tag = create(:post_tag)
+      section = create(:post_tag_section,
+                       post: post_tag.post,
+                       tag: post_tag.tag,
+                       begin_ms: 1000,
+                       end_ms: 2000)
+
+      expect(post_tag.sections).to contain_exactly(section)
+    end
+
+    it 'does not load sections for another tag on the same post' do
+      post = create(:post)
+      tag = create(:tag)
+      other_tag = create(:tag)
+
+      post_tag = create(:post_tag, post:, tag:)
+      create(:post_tag_section,
+             post:,
+             tag: other_tag,
+             begin_ms: 1000,
+             end_ms: 2000)
+
+      expect(post_tag.sections).to be_empty
+    end
+  end
+end
@@ -1,47 +0,0 @@
-require 'rails_helper'
-
-RSpec.describe 'error responses', type: :request do
-  describe 'manual input errors' do
-    it 'returns a stable payload for bad requests' do
-      get '/tags/name/%20/deerjikists'
-
-      expect(response).to have_http_status(:bad_request)
-      expect(json).to include(
-          'type' => 'bad_request',
-          'message' => be_present,
-          'errors' => {},
-          'base_errors' => [be_present])
-    end
-
-    it 'returns a stable field-error payload for unprocessable requests' do
-      member = create(:user, :member)
-      tag = create(:tag, :general, name: 'error_response_tag')
-      sign_in_as(member)
-
-      patch "/tags/#{ tag.id }", params: { category: 'nico' }
-
-      expect(response).to have_http_status(:unprocessable_entity)
-      expect(json).to include(
-          'type' => 'validation_error',
-          'message' => '入力内容を確認してください．',
-          'base_errors' => [])
-      expect(json.fetch('errors')).to include(
-          'category' => ['ニコタグは変更できません．'])
-    end
-  end
-
-  describe 'model validation errors' do
-    it 'returns field messages for model errors' do
-      user = create(:user)
-      sign_in_as(user)
-
-      put "/users/#{ user.id }", params: { name: 'a' * 256 }
-
-      expect(response).to have_http_status(:unprocessable_entity)
-      expect(json).to include(
-          'type' => 'validation_error',
-          'message' => '入力内容を確認してください．')
-      expect(json.fetch('errors').fetch('name')).to include(be_present)
-    end
-  end
-end
@@ -141,21 +141,16 @@ RSpec.describe 'Materials API', type: :request do
    context 'when logged in' do
      before { sign_in_as(guest_user) }

-      it 'returns 422 when tag is blank' do
+      it 'returns 400 when tag is blank' do
        post '/materials', params: { tag: '   ', file: dummy_upload }

-        expect(response).to have_http_status(:unprocessable_entity)
-        expect(json.fetch('errors')).to include(
-            'tag' => ['タグは必須です．'])
+        expect(response).to have_http_status(:bad_request)
      end

-      it 'returns 422 when both file and url are blank' do
+      it 'returns 400 when both file and url are blank' do
        post '/materials', params: { tag: 'material_create_blank' }

-        expect(response).to have_http_status(:unprocessable_entity)
-        expect(json.fetch('errors')).to include(
-            'file' => ['ファイルまたは URL は必須です．'],
-            'url' => ['ファイルまたは URL は必須です．'])
+        expect(response).to have_http_status(:bad_request)
      end

      it 'creates a material with an attached file' do
@@ -266,26 +261,21 @@ RSpec.describe 'Materials API', type: :request do
        expect(response).to have_http_status(:not_found)
      end

-      it 'returns 422 when tag is blank' do
+      it 'returns 400 when tag is blank' do
        put "/materials/#{ material.id }", params: {
          tag: '   ',
          file: dummy_upload
        }

-        expect(response).to have_http_status(:unprocessable_entity)
-        expect(json.fetch('errors')).to include(
-            'tag' => ['タグは必須です．'])
+        expect(response).to have_http_status(:bad_request)
      end

-      it 'returns 422 when both file and url are blank' do
+      it 'returns 400 when both file and url are blank' do
        put "/materials/#{ material.id }", params: {
          tag: 'material_update_no_payload'
        }

-        expect(response).to have_http_status(:unprocessable_entity)
-        expect(json.fetch('errors')).to include(
-            'file' => ['ファイルまたは URL は必須です．'],
-            'url' => ['ファイルまたは URL は必須です．'])
+        expect(response).to have_http_status(:bad_request)
      end

      it 'updates tag, url, file, and updated_by_user' do
@@ -3,68 +3,12 @@ require 'rails_helper'

 RSpec.describe 'NicoTags', type: :request do
  describe 'GET /tags/nico' do
-    it 'returns paginated tags and total count' do
-      create_list(:tag, 3, :nico)
-
-      get '/tags/nico', params: { page: 2, limit: 2 }
-
+    it 'returns tags and next_cursor when overflowing limit' do
+      create_list(:tag, 21, :nico)
+      get '/tags/nico', params: { limit: 20 }
      expect(response).to have_http_status(:ok)
-      expect(json['tags'].size).to eq(1)
-      expect(json['count']).to eq(3)
-    end
-
-    it 'filters by nico tag name, linked tag name, and link status' do
-      linked = create(:tag, :nico)
-      linked.tag_name.update!(name: 'nico:search_linked')
-      unlinked = create(:tag, :nico)
-      unlinked.tag_name.update!(name: 'nico:search_unlinked')
-      other = create(:tag, :nico)
-      other.tag_name.update!(name: 'nico:other')
-      destination = create(:tag, :general)
-      destination.tag_name.update!(name: 'destination_search')
-      NicoTagRelation.create!(nico_tag: linked, tag: destination)
-      NicoTagRelation.create!(nico_tag: other, tag: create(:tag, :general))
-
-      get '/tags/nico', params: {
-        name: 'search_',
-        linked_tag: 'destination_',
-        link_status: 'linked'
-      }
-
-      expect(response).to have_http_status(:ok)
-      expect(json['count']).to eq(1)
-      expect(json.fetch('tags').map { |tag| tag['id'] }).to eq([linked.id])
-
-      get '/tags/nico', params: { name: 'search_', link_status: 'unlinked' }
-
-      expect(json['count']).to eq(1)
-      expect(json.fetch('tags').map { |tag| tag['id'] }).to eq([unlinked.id])
-    end
-
-    it 'sorts by name and timestamps' do
-      older = create(:tag, :nico)
-      older.tag_name.update!(name: 'nico:a')
-      older.update_columns(created_at: 2.days.ago)
-      newer = create(:tag, :nico)
-      newer.tag_name.update!(name: 'nico:b')
-      newer.update_columns(created_at: 1.day.ago)
-      older_post_tag =
-        PostTag.create!(post: Post.create!(url: 'https://example.com/nico-older'), tag: older)
-      older_post_tag.update_columns(created_at: 1.hour.ago)
-      newer_post_tag =
-        PostTag.create!(post: Post.create!(url: 'https://example.com/nico-newer'), tag: newer)
-      newer_post_tag.update_columns(created_at: 2.hours.ago)
-
-      get '/tags/nico', params: { order: 'name:desc' }
-      expect(json.fetch('tags').map { |tag| tag['id'] }).to eq([newer.id, older.id])
-
-      get '/tags/nico', params: { order: 'created_at:asc' }
-      expect(json.fetch('tags').map { |tag| tag['id'] }).to eq([older.id, newer.id])
-
-      get '/tags/nico', params: { order: 'updated_at:desc' }
-      expect(json.fetch('tags').map { |tag| tag['id'] }).to eq([older.id, newer.id])
-      expect(Time.zone.parse(json.fetch('tags').first.fetch('recent_post_tag_created_at')))
-        .to be_within(1.second).of(older_post_tag.created_at)
+      expect(json['tags'].size).to eq(20)
+      expect(json['next_cursor']).to be_present
    end
  end

@@ -131,7 +75,7 @@ RSpec.describe 'NicoTags', type: :request do
      expect(versions.last.created_by_user_id).to eq(admin.id)
    end

-    it 'returns 422 when linked tag normalises to nico tag' do
+    it '400 when linked tag normalises to nico tag' do
      sign_in_as(member)

      other_nico = create(:tag, :nico, name: 'nico:linked_ng')
@@ -143,37 +87,7 @@ RSpec.describe 'NicoTags', type: :request do
        patch "/tags/nico/#{nico_tag.id}", params: { tags: 'linked_ng_alias' }
      }.not_to change(NicoTagVersion, :count)

-      expect(response).to have_http_status(:unprocessable_entity)
-      expect(json.fetch('errors')).to include(
-          'tags' => ['ニコニコ・タグ同士は連携できません．'])
-    end
-
-    it 'returns the tags field error when a nico tag is specified directly' do
-      sign_in_as(member)
-
-      patch "/tags/nico/#{nico_tag.id}", params: { tags: 'nico:linked_ng' }
-
-      expect(response).to have_http_status(:unprocessable_entity)
-      expect(json.fetch('errors')).to include(
-          'tags' => ['ニコニコ・タグ同士は連携できません．'])
-    end
-
-    it 'returns tag name validation errors on the tags field and rolls back created tags' do
-      sign_in_as(member)
-      TagNameSanitisationRule.create!(
-        priority: 1,
-        source_pattern: 'invalid',
-        replacement: 'valid'
-      )
-      nico_tag
-
-      expect {
-        patch "/tags/nico/#{nico_tag.id}", params: { tags: 'created_first invalid' }
-      }.not_to change(TagName, :count)
-
-      expect(response).to have_http_status(:unprocessable_entity)
-      expect(json.fetch('errors').fetch('tags')).to include(
-          a_string_including('タグ名 “invalid”:', '名前に使用できない文字が含まれてゐます．'))
+      expect(response).to have_http_status(:bad_request)
    end
  end
 end
@@ -57,23 +57,6 @@ RSpec.describe 'Posts API', type: :request do
    post_write_params({ base_version_no: base_version.version_no }.merge(params))
  end

-  def count_sql_queries
-    count = 0
-
-    callback = lambda do |_name, _started, _finished, _id, payload|
-      next if payload[:cached]
-      next if ['SCHEMA', 'TRANSACTION'].include?(payload[:name])
-
-      count += 1
-    end
-
-    ActiveSupport::Notifications.subscribed(callback, 'sql.active_record') do
-      yield
-    end
-
-    count
-  end
-
  let!(:tag_name) { TagName.create!(name: 'spec_tag') }
  let!(:tag)      { Tag.create!(tag_name: tag_name, category: :general) }

@@ -575,59 +558,6 @@ RSpec.describe 'Posts API', type: :request do
          expect(sibling_ids).to include(sibling_post.id)
        end
      end
-
-      it 'does not issue a query per tag or related post' do
-        user = create_member_user!
-
-        tags =
-            15.times.map do |i|
-              tag_name = TagName.create!(name: "show_query_tag_#{ i }")
-              tag = Tag.create!(tag_name:, category: :general)
-              TagName.create!(name: "show_query_alias_#{ i }", canonical: tag_name)
-              PostTag.create!(post: post_record, tag:)
-              tag
-            end
-
-        tags.each_cons(2) do |parent_tag, child_tag|
-          TagImplication.create!(parent_tag:, tag: child_tag)
-        end
-
-        parent_post = Post.create!(
-          title: 'query parent post',
-          url: 'https://example.com/query-parent-post'
-        )
-        sibling_post = Post.create!(
-          title: 'query sibling post',
-          url: 'https://example.com/query-sibling-post'
-        )
-        child_post = Post.create!(
-          title: 'query child post',
-          url: 'https://example.com/query-child-post'
-        )
-
-        PostImplication.create!(post: post_record, parent_post:)
-        PostImplication.create!(post: sibling_post, parent_post:)
-        PostImplication.create!(post: child_post, parent_post: post_record)
-
-        20.times do |i|
-          related_post = Post.create!(
-            title: "query related post #{ i }",
-            url: "https://example.com/query-related-post-#{ i }"
-          )
-          PostSimilarity.create!(post: post_record,
-                                 target_post: related_post,
-                                 cos: 1.0 - (i / 100.0))
-        end
-
-        query_count =
-            count_sql_queries do
-              get "/posts/#{ post_record.id }",
-                  headers: { 'X-Transfer-Code' => user.inheritance_code }
-            end
-
-        expect(response).to have_http_status(:ok)
-        expect(query_count).to be <= 45
-      end
    end

    context 'when post does not exist' do
@@ -704,7 +634,7 @@ RSpec.describe 'Posts API', type: :request do
            category: :nico)
      end

-      it 'returns 422 with tag field errors' do
+      it 'return 400' do
        sign_in_as(member)

        post '/posts', params: post_write_params(
@@ -714,13 +644,7 @@ RSpec.describe 'Posts API', type: :request do
          thumbnail: dummy_upload
        )

-        expect(response).to have_http_status(:unprocessable_entity), response.body
-        expect(json).to include(
-            'type' => 'validation_error',
-            'message' => '入力内容を確認してください．',
-            'base_errors' => [])
-        expect(json.fetch('errors')).to include(
-            'tags' => ['ニコニコ・タグは直接指定できません．'])
+        expect(response).to have_http_status(:bad_request), response.body
      end
    end

@@ -937,7 +861,7 @@ RSpec.describe 'Posts API', type: :request do
            category: :nico)
      end

-      it 'returns 422 with tag field errors' do
+      it 'return 400' do
        sign_in_as(member)

        put "/posts/#{post_record.id}", params: post_update_params(
@@ -945,13 +869,7 @@ RSpec.describe 'Posts API', type: :request do
            title: 'updated title',
            tags: 'nico:nico_tag')

-        expect(response).to have_http_status(:unprocessable_entity), response.body
-        expect(json).to include(
-            'type' => 'validation_error',
-            'message' => '入力内容を確認してください．',
-            'base_errors' => [])
-        expect(json.fetch('errors')).to include(
-            'tags' => ['ニコニコ・タグは直接指定できません．'])
+        expect(response).to have_http_status(:bad_request), response.body
      end
    end

@@ -275,30 +275,6 @@ RSpec.describe 'Tags deerjikists API', type: :request do
        end
      end

-      context 'when a row is invalid' do
-        let(:payload) do
-          [
-            { platform: '', code: code1 },
-          ]
-        end
-
-        it 'returns 422 with indexed field errors and does not replace existing deerjikists' do
-          Deerjikist.create!(platform: platform1, code: code1, tag: tag)
-
-          expect {
-            do_request
-          }.not_to change { Deerjikist.where(tag: tag).map { |d| [d.platform, d.code] } }
-
-          expect(response).to have_http_status(:unprocessable_entity)
-          expect(json).to include(
-              'type' => 'validation_error',
-              'message' => '入力内容を確認してください．',
-              'base_errors' => [])
-          expect(json.fetch('errors')).to include(
-              'deerjikists.0.platform' => [be_present])
-        end
-      end
-
      context 'when youtube code is handle' do
        let(:channel_id) { 'UCabcdefghijklmnopqrstuv' }
        let(:payload) do
@@ -90,14 +90,12 @@ RSpec.describe 'Users', type: :request do
      expect(response).to have_http_status(:unauthorized)
    end

-    it 'returns 422 when name is blank' do
+    it 'returns 400 when name is blank' do
      put "/users/#{user.id}",
          params: { name: '   ' },
          headers: auth_headers(user)

-      expect(response).to have_http_status(:unprocessable_entity)
-      expect(json.fetch('errors')).to include(
-          'name' => ['名前は必須です．'])
+      expect(response).to have_http_status(:bad_request)
    end

    it 'updates name and returns user slice' do
@@ -62,7 +62,6 @@ const RouteTransitionWrapper = ({ user, setUser }: {
 	  <Route path="/tags/:id" element={<TagDetailPage/>}/>
 	  <Route path="/tags/:id/deerjikists" element={<DeerjikistDetailPage/>}/>
 	  <Route path="/tags/nico" element={<NicoTagListPage user={user}/>}/>
-	  <Route path="/nico/tags" element={<NicoTagListPage user={user}/>}/>
 	  <Route path="/tags/changes" element={<TagHistoryPage/>}/>
 	  <Route path="/theatres/:id" element={<TheatreDetailPage/>}/>
 	  <Route path="/materials" element={<MaterialBasePage/>}>
@@ -159,4 +158,4 @@ const App: FC = () => {
      </>)
 }

-export default App
+export default App
@@ -2,36 +2,34 @@ import { useEffect, useState } from 'react'

 import PostFormTagsArea from '@/components/PostFormTagsArea'
 import PostOriginalCreatedTimeField from '@/components/PostOriginalCreatedTimeField'
-import FieldError from '@/components/common/FieldError'
-import FormField from '@/components/common/FormField'
+import Label from '@/components/common/Label'
 import { useDialogue } from '@/components/dialogues/DialogueProvider'
 import { Button } from '@/components/ui/button'
 import { toast } from '@/components/ui/use-toast'
 import { isApiError } from '@/lib/api'
 import { updatePost } from '@/lib/posts'
-import { inputClass } from '@/lib/utils'
-import { useValidationErrors } from '@/lib/useValidationErrors'
+import { msToTime } from '@/lib/utils'

 import type { FC, FormEvent } from 'react'

-import type { Post, Tag } from '@/types'
-
-type PostFormField =
-    'parentPostIds' | 'tags' | 'originalCreatedAt'
+import type { Post, TagWithSections } from '@/types'


-const tagsToStr = (tags: Tag[]): string => {
-  const result: Tag[] = []
+const tagsToStr = (tags: TagWithSections[]): string => {
+  const result: Omit<TagWithSections, 'children'>[] = []

-  const walk = (tag: Tag) => {
+  const walk = (tag: TagWithSections) => {
    const { children, ...rest } = tag
    result.push (rest)
-    children?.forEach (walk)
+    children.forEach (walk)
  }

  tags.filter (t => t.category !== 'nico').forEach (walk)

-  return [...(new Set (result.map (t => t.name)))].join (' ')
+  return [...(new Set (result.map (t =>
+      `${ t.name }${ t.sections
+		     .map (s => `[${ msToTime (s.beginMs) }-${ msToTime (s.endMs) }]`)
+		     .join ('') }`)))].join (' ')
 }


@@ -41,8 +39,6 @@ type Props = { post:    Post

 const PostEditForm: FC<Props> = ({ post, onSave }) => {
  const [disabled, setDisabled] = useState (false)
-  const { baseErrors, fieldErrors, clearValidationErrors, applyValidationError } =
-      useValidationErrors<PostFormField> ()
  const [originalCreatedBefore, setOriginalCreatedBefore] =
      useState<string | null> (post.originalCreatedBefore)
  const [originalCreatedFrom, setOriginalCreatedFrom] =
@@ -55,8 +51,6 @@ const PostEditForm: FC<Props> = ({ post, onSave }) => {
  const dialogue = useDialogue ()

  const update = async (...args: Parameters<typeof updatePost>) => {
-    clearValidationErrors ()
-
    try
    {
      const data = await updatePost (...args)
@@ -77,14 +71,7 @@ const PostEditForm: FC<Props> = ({ post, onSave }) => {

      if (response?.status !== 409)
 	{
-	  if (applyValidationError (e))
-	    {
-	      toast ({ description: '更新はできなかったよ……' })
-	      return
-	    }
-
-	  toast ({ title: '失敗……', description: '入力を確認してください．' })
-
+	  toast ({ description: '更新はできなかったよ……' })
 	  return
 	}

@@ -134,43 +121,38 @@ const PostEditForm: FC<Props> = ({ post, onSave }) => {
  }

  useEffect (() => {
-    setTags(tagsToStr (post.tags))
+    setTags (tagsToStr (post.tags))
  }, [post])

  return (
      <form onSubmit={handleSubmit} className="max-w-xl pt-2 space-y-4">
-	<FieldError messages={baseErrors}/>
-
 	{/* タイトル */}
-	<FormField label="タイトル">
-	  {({ invalid }) => (
-	      <input
-		  type="text"
-		  disabled={disabled}
-		  className={inputClass (invalid)}
-		  value={title ?? ''}
-		  onChange={ev => setTitle (ev.target.value)}/>)}
-	</FormField>
+	<div>
+	  <Label>タイトル</Label>
+	  <input
+	      type="text"
+	      disabled={disabled}
+	      className="w-full border rounded p-2"
+	      value={title ?? ''}
+	      onChange={ev => setTitle (ev.target.value)}/>
+	</div>

 	{/* 親投稿 */}
-	<FormField label="親投稿" messages={fieldErrors.parentPostIds}>
-	  {({ describedBy, invalid }) => (
-	      <input
-		  type="text"
-		  disabled={disabled}
-		  value={parentPostIds}
-		  onChange={e => setParentPostIds (e.target.value)}
-		  aria-describedby={describedBy}
-		  aria-invalid={invalid}
-		  className={inputClass (invalid)}/>)}
-	</FormField>
+	<div>
+	  <Label>親投稿</Label>
+	  <input
+	      type="text"
+	      disabled={disabled}
+	      value={parentPostIds}
+	      onChange={e => setParentPostIds (e.target.value)}
+	      className="w-full border p-2 rounded"/>
+	</div>

 	{/* タグ */}
 	<PostFormTagsArea
 	    disabled={disabled}
 	    tags={tags}
-	    setTags={setTags}
-	    errors={fieldErrors.tags}/>
+	    setTags={setTags}/>

 	{/* オリジナルの作成日時 */}
 	<PostOriginalCreatedTimeField
@@ -178,11 +160,12 @@ const PostEditForm: FC<Props> = ({ post, onSave }) => {
 	    originalCreatedFrom={originalCreatedFrom}
 	    setOriginalCreatedFrom={setOriginalCreatedFrom}
 	    originalCreatedBefore={originalCreatedBefore}
-	    setOriginalCreatedBefore={setOriginalCreatedBefore}
-	    errors={fieldErrors.originalCreatedAt}/>
+	    setOriginalCreatedBefore={setOriginalCreatedBefore}/>

 	{/* 送信 */}
-	<Button type="submit" disabled={disabled}>
+	<Button
+	    type="submit"
+	    disabled={disabled}>
 	  更新
 	</Button>
      </form>)
@@ -3,7 +3,7 @@
 import { useRef, useState } from 'react'

 import TagSearchBox from '@/components/TagSearchBox'
-import FormField from '@/components/common/FormField'
+import Label from '@/components/common/Label'
 import TextArea from '@/components/common/TextArea'
 import { apiGet } from '@/lib/api'

@@ -33,11 +33,10 @@ const replaceToken = (value: string, start: number, end: number, text: string) =

 type Props = Omit<ComponentPropsWithoutRef<'textarea'>, 'value' | 'onChange' | 'onBlur'> & {
    tags:     string
-    setTags:  (tags: string) => void
-    errors?:  string[] }
+    setTags:  (tags: string) => void }


-const PostFormTagsArea: FC<Props> = ({ tags, setTags, errors, ...rest }) => {
+const PostFormTagsArea: FC<Props> = ({ tags, setTags, ...rest }) => {
  const ref = useRef<HTMLTextAreaElement> (null)

  const [bounds, setBounds] = useState<{ start: number; end: number }> ({ start: 0, end: 0 })
@@ -74,34 +73,30 @@ const PostFormTagsArea: FC<Props> = ({ tags, setTags, errors, ...rest }) => {
  }

  return (
-      <FormField className="relative w-full" label="タグ" messages={errors}>
-	{({ describedBy, invalid }) => (
-	    <>
-	      <TextArea
-		  {...rest}
-		  ref={ref}
-		  value={tags}
-		  aria-describedby={describedBy}
-		  invalid={invalid}
-		  onChange={ev => setTags (ev.target.value)}
-		  onSelect={async (ev: SyntheticEvent<HTMLTextAreaElement>) => {
-		    const pos = (ev.target as HTMLTextAreaElement).selectionStart
-		    await recompute (pos)
-		  }}
-		  onFocus={() => setFocused (true)}
-		  onBlur={() => {
-		    setFocused (false)
-		    setSuggestionsVsbl (false)
-		  }}/>
-	      {focused && (
-		  <TagSearchBox
-		      suggestions={suggestionsVsbl && suggestions.length > 0
-				   ? suggestions
-				   : [] as Tag[]}
-		      activeIndex={-1}
-		      onSelect={handleTagSelect}/>)}
-	    </>)}
-      </FormField>)
+      <div className="relative w-full">
+	<Label>タグ</Label>
+	<TextArea
+	    {...rest}
+	    ref={ref}
+	    value={tags}
+	    onChange={ev => setTags (ev.target.value)}
+	    onSelect={async (ev: SyntheticEvent<HTMLTextAreaElement>) => {
+	      const pos = (ev.target as HTMLTextAreaElement).selectionStart
+	      await recompute (pos)
+	    }}
+	    onFocus={() => setFocused (true)}
+	    onBlur={() => {
+	      setFocused (false)
+	      setSuggestionsVsbl (false)
+	    }}/>
+	{focused && (
+	    <TagSearchBox
+		suggestions={suggestionsVsbl && suggestions.length > 0
+			     ? suggestions
+			     : [] as Tag[]}
+		activeIndex={-1}
+		onSelect={handleTagSelect}/>)}
+      </div>)
 }

-export default PostFormTagsArea
+export default PostFormTagsArea
@@ -1,5 +1,5 @@
 import DateTimeField from '@/components/common/DateTimeField'
-import FormField from '@/components/common/FormField'
+import Label from '@/components/common/Label'
 import { Button } from '@/components/ui/button'

 import type { FC } from 'react'
@@ -9,81 +9,68 @@ type Props = {
    originalCreatedFrom:      string | null
    setOriginalCreatedFrom:   (x: string | null) => void
    originalCreatedBefore:    string | null
-    setOriginalCreatedBefore: (x: string | null) => void
-    errors?:                  string[] }
+    setOriginalCreatedBefore: (x: string | null) => void }


-const PostOriginalCreatedTimeField: FC<Props> = (
-    { disabled,
-      originalCreatedFrom,
-      setOriginalCreatedFrom,
-      originalCreatedBefore,
-      setOriginalCreatedBefore,
-      errors }: Props,
-) => (
-    <FormField label="オリジナルの作成日時" messages={errors}>
-      {({ describedBy, invalid }) => (
-	  <>
-	    <div className="my-1 flex">
-	      <div className="w-80">
-		<DateTimeField
-		    className="mr-2"
-		    disabled={disabled ?? false}
-		    aria-describedby={describedBy}
-		    aria-invalid={invalid}
-		    invalid={invalid}
-		    value={originalCreatedFrom ?? undefined}
-		    onChange={setOriginalCreatedFrom}
-		    onBlur={ev => {
-		      const v = ev.target.value
-		      if (!(v))
-			return
+const PostOriginalCreatedTimeField: FC<Props> = ({ disabled,
+		   originalCreatedFrom,
+		   setOriginalCreatedFrom,
+		   originalCreatedBefore,
+		   setOriginalCreatedBefore }) => (
+    <div>
+      <Label>オリジナルの作成日時</Label>
+      <div className="my-1 flex">
+	<div className="w-80">
+	  <DateTimeField
+	      className="mr-2"
+	      disabled={disabled ?? false}
+	      value={originalCreatedFrom ?? undefined}
+	      onChange={setOriginalCreatedFrom}
+	      onBlur={ev => {
+		const v = ev.target.value
+		if (!(v))
+		  return

-		      const d = new Date (v)
-		      if (d.getMinutes () === 0 && d.getHours () === 0)
-			d.setDate (d.getDate () + 1)
-		      else
-			d.setMinutes (d.getMinutes () + 1)
-		      setOriginalCreatedBefore (d.toISOString ())
-		    }}/>
-		以降
-	      </div>
-	      <div>
-		<Button
-		    className="bg-gray-600 text-white rounded"
-		    disabled={disabled}
-		    onClick={() => {
-		      setOriginalCreatedFrom (null)
-		    }}>
-		  リセット
-		</Button>
-	      </div>
-	    </div>
+		const d = new Date (v)
+		if (d.getMinutes () === 0 && d.getHours () === 0)
+		  d.setDate (d.getDate () + 1)
+		else
+		  d.setMinutes (d.getMinutes () + 1)
+		setOriginalCreatedBefore (d.toISOString ())
+	      }}/>
+	  以降
+	</div>
+	<div>
+	  <Button
+	      className="bg-gray-600 text-white rounded"
+	      disabled={disabled}
+	      onClick={() => {
+		setOriginalCreatedFrom (null)
+	      }}>
+	    リセット
+	  </Button>
+	</div>
+      </div>
+      <div className="my-1 flex">
+	<div className="w-80">
+	  <DateTimeField
+	      className="mr-2"
+	      disabled={disabled}
+	      value={originalCreatedBefore ?? undefined}
+	      onChange={setOriginalCreatedBefore}/>
+	  より前
+	</div>
+	<div>
+	  <Button
+	      className="bg-gray-600 text-white rounded"
+	      disabled={disabled}
+	      onClick={() => {
+		setOriginalCreatedBefore (null)
+	      }}>
+	    リセット
+	  </Button>
+	</div>
+      </div>
+    </div>)

-	    <div className="my-1 flex">
-	      <div className="w-80">
-		<DateTimeField
-		    className="mr-2"
-		    disabled={disabled}
-		    aria-describedby={describedBy}
-		    aria-invalid={invalid}
-		    invalid={invalid}
-		    value={originalCreatedBefore ?? undefined}
-		    onChange={setOriginalCreatedBefore}/>
-		より前
-	      </div>
-	      <div>
-		<Button
-		    className="bg-gray-600 text-white rounded"
-		    disabled={disabled}
-		    onClick={() => {
-		      setOriginalCreatedBefore (null)
-		    }}>
-		  リセット
-		</Button>
-	      </div>
-	    </div>
-	  </>)}
-    </FormField>)
-
-export default PostOriginalCreatedTimeField
+export default PostOriginalCreatedTimeField
@@ -26,13 +26,13 @@ import { dateString, originalCreatedAtString } from '@/lib/utils'
 import type { DragEndEvent } from '@dnd-kit/core'
 import type { FC, MutableRefObject, ReactNode } from 'react'

-import type { Category, Post, Tag } from '@/types'
+import type { Category, Post, TagWithSections } from '@/types'

-type TagByCategory = { [key in Category]: Tag[] }
+type TagByCategory = { [key in Category]: TagWithSections[] }


 const renderTagTree = (
-    tag:              Tag,
+    tag:              TagWithSections,
    nestLevel:        number,
    path:             string,
    suppressClickRef: MutableRefObject<boolean>,
@@ -63,7 +63,7 @@ const renderTagTree = (


 const isDescendant = (
-    root:     Tag,
+    root:     TagWithSections,
    targetId: number,
 ): boolean => {
  if (!(root.children))
@@ -84,8 +84,8 @@ const isDescendant = (
 const findTag = (
    byCat:  TagByCategory,
    id:     number,
-): Tag | undefined => {
-  const walk = (nodes: Tag[]): Tag | undefined => {
+): TagWithSections | undefined => {
+  const walk = (nodes: TagWithSections[]): TagWithSections | undefined => {
    for (const t of nodes)
      {
 	if (t.id === id)
@@ -167,7 +167,7 @@ const TagDetailSidebar: FC<Props> = ({ post, sp }) => {
      }

    for (const cat of Object.keys (tagsTmp) as (keyof typeof tagsTmp)[])
-      tagsTmp[cat].sort ((tagA: Tag, tagB: Tag) => tagA.name < tagB.name ? -1 : 1)
+      tagsTmp[cat].sort ((tagA: TagWithSections, tagB: TagWithSections) => tagA.name < tagB.name ? -1 : 1)

    return tagsTmp
  }, [post])
@@ -378,4 +378,4 @@ const TagDetailSidebar: FC<Props> = ({ post, sp }) => {
      </SidebarComponent>)
 }

-export default TagDetailSidebar
+export default TagDetailSidebar
@@ -4,7 +4,6 @@ import { useEffect, useState } from 'react'
 import { useNavigate, useLocation } from 'react-router-dom'

 import { apiGet } from '@/lib/api'
-import { inputClass } from '@/lib/utils'

 import TagSearchBox from './TagSearchBox'

@@ -111,12 +110,11 @@ const TagSearch: FC = () => {
 	       onFocus={() => setSuggestionsVsbl (true)}
 	       onBlur={() => setSuggestionsVsbl (false)}
 	       onKeyDown={handleKeyDown}
-	       className={inputClass (false,
-				      'px-3 py-2 dark:border-gray-600 dark:bg-gray-800 dark:text-white')}/>
+	       className="w-full px-3 py-2 border rounded dark:border-gray-600 dark:bg-gray-800 dark:text-white"/>
 	<TagSearchBox suggestions={suggestionsVsbl && suggestions.length ? suggestions : [] as Tag[]}
 		      activeIndex={activeIndex}
 		      onSelect={handleTagSelect}/>
      </div>)
 }

-export default TagSearch
+export default TagSearch
@@ -22,11 +22,10 @@ type Props = Omit<ComponentPropsWithoutRef<'input'>, 'onChange'> & {
    value?:     string
    onChange?:  (isoUTC: string | null) => void
    className?: string
-    onBlur?:    (ev: FocusEvent<HTMLInputElement>) => void
-    invalid?:   boolean }
+    onBlur?:    (ev: FocusEvent<HTMLInputElement>) => void }


-const DateTimeField: FC<Props> = ({ value, onChange, className, onBlur, invalid, ...rest }) => {
+const DateTimeField: FC<Props> = ({ value, onChange, className, onBlur, ...rest }) => {
  const [local, setLocal] = useState ('')

  useEffect (() => {
@@ -36,19 +35,9 @@ const DateTimeField: FC<Props> = ({ value, onChange, className, onBlur, invalid,
  return (
      <input
 	  {...rest}
-	  className={cn ('border rounded p-2',
-			 (invalid
-			  ? ['border-red-500 bg-red-50 text-red-900',
-			     'focus:border-red-500 focus:outline-none',
-			     'focus:ring-2 focus:ring-red-200',
-			     'dark:border-red-500 dark:bg-red-950/30 dark:text-red-100']
-			  : ['border-gray-300',
-			     'focus:border-blue-500 focus:outline-none',
-			     'focus:ring-2 focus:ring-blue-200']),
-			 className)}
+	  className={cn ('border rounded p-2', className)}
 	  type="datetime-local"
 	  value={local}
-	  aria-invalid={invalid}
 	  onChange={ev => {
 	    const v = ev.target.value
 	    setLocal (v)
@@ -57,4 +46,4 @@ const DateTimeField: FC<Props> = ({ value, onChange, className, onBlur, invalid,
 	  onBlur={onBlur}/>)
 }

-export default DateTimeField
+export default DateTimeField
@@ -1,18 +0,0 @@
-import type { FC } from 'react'
-
-type Props = { id?:        string
-	       messages?:  string[] }
-
-
-export const FieldError: FC<Props> = ({ id, messages }: Props) => {
-  if (!(messages) || messages.length === 0)
-    return null
-
-  return (
-      <ul id={id} className="mt-1 space-y-1 text-red-700 dark:text-red-300">
-	{messages.map ((message, i) => <li key={i}>{message}</li>)}
-      </ul>)
-}
-
-
-export default FieldError
@@ -1,36 +0,0 @@
-import { useId } from 'react'
-
-import FieldError from '@/components/common/FieldError'
-import Label from '@/components/common/Label'
-import { cn } from '@/lib/utils'
-
-import type { FC, ReactNode } from 'react'
-
-type FieldState = { describedBy?: string
-		    invalid:      boolean }
-
-type Props = {
-    children:   (state: FieldState) => ReactNode
-    checkBox?:   { label:    string
-		   checked:  boolean
-		   onChange: (event: React.ChangeEvent<HTMLInputElement>) => void }
-    className?:  string
-    label:      ReactNode
-    messages?:  string[] }
-
-
-const FormField: FC<Props> = ({ children, checkBox, className, label, messages }: Props) => {
-  const id = useId ()
-  const invalid = messages != null && messages.length > 0
-  const errorId = invalid ? `${ id }-error` : undefined
-
-  return (
-      <div className={cn (className)}>
-	<Label checkBox={checkBox} invalid={invalid}>{label}</Label>
-	{children ({ describedBy: errorId, invalid })}
-	<FieldError id={errorId} messages={messages}/>
-      </div>)
-}
-
-
-export default FormField
@@ -1,39 +1,32 @@
 import React from 'react'

-import { cn } from '@/lib/utils'
-
 import type { FC } from 'react'

 type Props = { children:  React.ReactNode
-	       checkBox?: { label:    string
-			    checked:  boolean
-			    onChange: (event: React.ChangeEvent<HTMLInputElement>) => void }
-	       invalid?:  boolean }
+               checkBox?: { label:    string
+                            checked:  boolean
+                            onChange: (event: React.ChangeEvent<HTMLInputElement>) => void } }


-const Label: FC<Props> = ({ children, checkBox, invalid }: Props) => {
-  const labelClassName = cn ('block font-semibold mb-1',
-			     invalid && 'text-red-700 dark:text-red-300')
-
+const Label: FC<Props> = ({ children, checkBox }) => {
  if (!(checkBox))
    {
      return (
-	  <label className={labelClassName}>
-	    {children}
-	  </label>)
+          <label className="block font-semibold mb-1">
+            {children}
+          </label>)
    }

  return (
      <div className="flex gap-2 mb-1">
-	<label className="flex-1 block font-semibold">{children}</label>
-	<label className="flex items-center block gap-1">
-	  <input type="checkbox"
-		 checked={checkBox.checked}
-		 onChange={checkBox.onChange}/>
-	  {checkBox.label}
-	</label>
+        <label className="flex-1 block font-semibold">{children}</label>
+        <label className="flex items-center block gap-1">
+          <input type="checkbox"
+                 checked={checkBox.checked}
+                 onChange={checkBox.onChange}/>
+          {checkBox.label}
+        </label>
      </div>)
 }

-
 export default Label
@@ -2,7 +2,6 @@ import { useState } from 'react'

 import TagSearchBox from '@/components/TagSearchBox'
 import { apiGet } from '@/lib/api'
-import { inputClass } from '@/lib/utils'

 import type { FC, ChangeEvent, KeyboardEvent } from 'react'

@@ -10,13 +9,10 @@ import type { Tag } from '@/types'


 type Props = {
-    describedBy?:  string
-    invalid?:      boolean
-    value:         string
-    setValue:      (value: string) => void }
+    value:      string
+    setValue:   (value: string) => void }

-
-const TagInput: FC<Props> = ({ describedBy, invalid, value, setValue }) => {
+const TagInput: FC<Props> = ({ value, setValue }) => {
  const [activeIndex, setActiveIndex] = useState (-1)
  const [suggestions, setSuggestions] = useState<Tag[]> ([])
  const [suggestionsVsbl, setSuggestionsVsbl] = useState (false)
@@ -89,14 +85,12 @@ const TagInput: FC<Props> = ({ describedBy, invalid, value, setValue }) => {
      <div className="relative">
 	<input
 	    type="text"
-	    aria-describedby={describedBy}
-	    aria-invalid={invalid}
 	    value={value}
 	    onChange={whenChanged}
 	    onFocus={() => setSuggestionsVsbl (true)}
 	    onBlur={() => setSuggestionsVsbl (false)}
 	    onKeyDown={handleKeyDown}
-	    className={inputClass (invalid)}/>
+	    className="w-full border p-2 rounded"/>
 	<TagSearchBox
 	    suggestions={
 		suggestionsVsbl && suggestions.length > 0 ? suggestions : [] as Tag[]}
@@ -105,4 +99,4 @@ const TagInput: FC<Props> = ({ describedBy, invalid, value, setValue }) => {
      </div>)
 }

-export default TagInput
+export default TagInput
@@ -1,25 +1,9 @@
 import { forwardRef } from 'react'

-import { cn } from '@/lib/utils'
-
 import type { TextareaHTMLAttributes } from 'react'

-type Props = TextareaHTMLAttributes<HTMLTextAreaElement> & { invalid?: boolean }
+type Props = TextareaHTMLAttributes<HTMLTextAreaElement>


-export default forwardRef<HTMLTextAreaElement, Props> (
-    ({ className, invalid = false, ...props }, ref) => (
-	<textarea
-	    ref={ref}
-	    aria-invalid={invalid}
-	    className={cn ('rounded border w-full p-2 h-32',
-			   (invalid
-			    ? ['border-red-500 bg-red-50 text-red-900',
-			       'focus:border-red-500 focus:outline-none focus:ring-2',
-			       'focus:ring-red-200',
-			       'dark:border-red-500 dark:bg-red-950/30 dark:text-red-100']
-			    : ['border-gray-300',
-			       'focus:border-blue-500 focus:outline-none focus:ring-2',
-			       'focus:ring-blue-200']),
-			   className)}
-	    {...props}/>))
+export default forwardRef<HTMLTextAreaElement, Props> (({ ...props }, ref) => (
+    <textarea ref={ref} className="rounded border w-full p-2 h-32" {...props}/>))
@@ -1,79 +0,0 @@
-import { describe, expect, it, vi } from 'vitest'
-
-const api = vi.hoisted (() => ({
-  isApiError: vi.fn (),
-}))
-
-vi.mock ('@/lib/api', () => api)
-
-describe ('extractValidationError', () => {
-  it ('extracts field and base errors from 422 validation responses', async () => {
-    api.isApiError.mockReturnValueOnce (true)
-
-    const { extractValidationError } = await import ('@/lib/apiErrors')
-    const validationError = extractValidationError<'name'> ({
-      response: {
-        status: 422,
-        data:   {
-          type:        'validation_error',
-          message:     '入力内容を確認してください．',
-          errors:      { name: ['名前は必須です．'] },
-          base_errors: ['全体エラー'],
-        },
-      },
-    })
-
-    expect (validationError).toEqual ({
-      message:     '入力内容を確認してください．',
-      fieldErrors: { name: ['名前は必須です．'] },
-      baseErrors:  ['全体エラー'],
-    })
-  })
-
-  it ('preserves dotted field keys for indexed form rows', async () => {
-    api.isApiError.mockReturnValueOnce (true)
-
-    const { extractValidationError } = await import ('@/lib/apiErrors')
-    const validationError = extractValidationError<'deerjikists.0.platform'> ({
-      response: {
-        status: 422,
-        data:   {
-          type:        'validation_error',
-          errors:      { 'deerjikists.0.platform': ['プラットフォームを入力してください．'] },
-          base_errors: [],
-        },
-      },
-    })
-
-    expect (validationError?.fieldErrors).toEqual ({
-      'deerjikists0Platform': ['プラットフォームを入力してください．'],
-    })
-  })
-
-  it ('does not treat 400 bad requests as form validation errors', async () => {
-    api.isApiError.mockReturnValueOnce (true)
-
-    const { extractValidationError } = await import ('@/lib/apiErrors')
-    const validationError = extractValidationError ({
-      response: {
-        status: 400,
-        data:   {
-          type:        'bad_request',
-          message:     'リクエストが不正です．',
-          errors:      {},
-          base_errors: ['リクエストが不正です．'],
-        },
-      },
-    })
-
-    expect (validationError).toBeNull ()
-  })
-
-  it ('ignores non-api errors', async () => {
-    api.isApiError.mockReturnValueOnce (false)
-
-    const { extractValidationError } = await import ('@/lib/apiErrors')
-
-    expect (extractValidationError (new Error ('network'))).toBeNull ()
-  })
-})
@@ -1,36 +0,0 @@
-import toCamel from 'camelcase-keys'
-
-import { isApiError } from '@/lib/api'
-
-export type FieldErrors<T extends string = string> = Partial<Record<T, string[]>>
-
-export type ValidationError<T extends string = string> =
-    { message:      string
-      fieldErrors:  FieldErrors<T>
-      baseErrors:   string[] }
-
-type RawValidationError = { type?:        string
-			    message?:     string
-			    errors?:      Record<string, string[]>
-			    baseErrors?:  string[] }
-
-
-export const extractValidationError = <T extends string = string> (err: unknown) => {
-  if (!(isApiError (err)) || err.response?.status !== 422)
-    return null
-
-  const rawData = toCamel ((err.response.data ?? { }) as Record<string, unknown>,
-			   { deep: true }) as RawValidationError
-  const data: RawValidationError = {
-      type:       rawData.type as string | undefined,
-      message:    rawData.message as string | undefined,
-      errors:     rawData.errors as Record<string, string[]> | undefined,
-      baseErrors: rawData.baseErrors as string[] | undefined }
-
-  if (data.type !== 'validation_error' && !(data.errors))
-    return null
-
-  return { message: data.message ?? '入力内容を確認してください．',
-	   fieldErrors: (data.errors ?? { }) as FieldErrors<T>,
-	   baseErrors: data.baseErrors ?? [] }
-}
@@ -10,7 +10,6 @@ const postsApi = vi.hoisted (() => ({
 }))

 const tagsApi = vi.hoisted (() => ({
-  fetchNicoTags:   vi.fn (),
  fetchTag:        vi.fn (),
  fetchTagByName:  vi.fn (),
  fetchTagChanges: vi.fn (),
@@ -38,7 +37,6 @@ describe ('prefetchForURL', () => {
    postsApi.fetchPost.mockResolvedValue ({ id: 1 })
    postsApi.fetchPostChanges.mockResolvedValue ({ versions: [], count: 0 })
    tagsApi.fetchTags.mockResolvedValue ({ tags: [], count: 0 })
-    tagsApi.fetchNicoTags.mockResolvedValue ({ tags: [], count: 0 })
    tagsApi.fetchTag.mockResolvedValue ({ id: 1 })
    tagsApi.fetchTagByName.mockResolvedValue (null)
    tagsApi.fetchTagChanges.mockResolvedValue ({ versions: [], count: 0 })
@@ -87,32 +85,6 @@ describe ('prefetchForURL', () => {
    )
  })

-  it ('prefetches nico tag indexes and their alias from query parameters', async () => {
-    await prefetchForURL (
-        qc (),
-        'http://localhost/tags/nico?name=source&linked_tag=destination'
-	    + '&link_status=linked&page=3&limit=10',
-    )
-    await prefetchForURL (qc (), 'http://localhost/nico/tags?page=2')
-
-    expect (tagsApi.fetchNicoTags).toHaveBeenNthCalledWith (1, {
-      name:       'source',
-      linkedTag:  'destination',
-      linkStatus: 'linked',
-      page:       3,
-      limit:      10,
-      order:      'updated_at:desc',
-    })
-    expect (tagsApi.fetchNicoTags).toHaveBeenNthCalledWith (2, {
-      name:       '',
-      linkedTag:  '',
-      linkStatus: 'all',
-      page:       2,
-      limit:      20,
-      order:      'updated_at:desc',
-    })
-  })
-
  it ('prefetches wiki show pages and related tag/post data', async () => {
    wikiApi.fetchWikiPageByTitle.mockResolvedValueOnce ({
      id:    3,
@@ -3,7 +3,7 @@ import { match } from 'path-to-regexp'

 import { fetchPost, fetchPosts, fetchPostChanges } from '@/lib/posts'
 import { postsKeys, tagsKeys, wikiKeys } from '@/lib/queryKeys'
-import { fetchNicoTags, fetchTagByName, fetchTag, fetchTagChanges, fetchTags } from '@/lib/tags'
+import { fetchTagByName, fetchTag, fetchTagChanges, fetchTags } from '@/lib/tags'
 import { fetchWikiPage,
 	 fetchWikiPageByTitle,
 	 fetchWikiPages } from '@/lib/wiki'
@@ -170,24 +170,6 @@ const prefetchTagsIndex: Prefetcher = async (qc, url) => {
 }


-const prefetchNicoTagsIndex: Prefetcher = async (qc, url) => {
-  const keys = {
-      name:       url.searchParams.get ('name') ?? '',
-      linkedTag:  url.searchParams.get ('linked_tag') ?? '',
-      linkStatus: (url.searchParams.get ('link_status') || 'all') as
-		  'all' | 'linked' | 'unlinked',
-      page:       Number (url.searchParams.get ('page') || 1),
-      limit:      Number (url.searchParams.get ('limit') || 20),
-      order:      (url.searchParams.get ('order') || 'updated_at:desc') as
-		  'name:asc' | 'name:desc' | 'created_at:asc' | 'created_at:desc'
-		  | 'updated_at:asc' | 'updated_at:desc' }
-
-  await qc.prefetchQuery ({
-      queryKey: tagsKeys.nicoIndex (keys),
-      queryFn:  () => fetchNicoTags (keys) })
-}
-
-
 const prefetchTagShow: Prefetcher = async (qc, url) => {
  const m = mTag (url.pathname)
  if (!(m))
@@ -224,8 +206,6 @@ export const routePrefetchers: { test: (u: URL) => boolean; run: Prefetcher }[]
 		  && Boolean (mWiki (u.pathname))),
      run: prefetchWikiPageShow },
    { test: u => u.pathname === '/tags', run: prefetchTagsIndex },
-    { test: u => ['/tags/nico', '/nico/tags'].includes (u.pathname),
-      run: prefetchNicoTagsIndex },
    { test: u => (!(['/tags/nico', '/tags/changes'].includes (u.pathname))
 		  && Boolean (mTag (u.pathname))),
      run: prefetchTagShow },
@@ -1,4 +1,4 @@
-import type { FetchNicoTagsParams, FetchPostsParams, FetchTagsParams } from '@/types'
+import type { FetchPostsParams, FetchTagsParams } from '@/types'

 export const postsKeys = {
    root:     ['posts'] as const,
@@ -11,8 +11,6 @@ export const postsKeys = {
 export const tagsKeys = {
    root:         ['tags'] as const,
    index:        (p: FetchTagsParams) => ['tags', 'index', p] as const,
-    nicoRoot:     ['tags', 'nico'] as const,
-    nicoIndex:    (p: FetchNicoTagsParams) => ['tags', 'nico', 'index', p] as const,
    show:         (name: string) => ['tags', name] as const,
    changes:      (p: { id?: string; page: number; limit: number }) =>
 		      ['tags', 'changes', p] as const,
@@ -1,11 +1,6 @@
 import { apiGet } from '@/lib/api'

-import type { Deerjikist,
-	      FetchNicoTagsParams,
-	      FetchTagsParams,
-	      NicoTag,
-	      Tag,
-	      TagVersion } from '@/types'
+import type { Deerjikist, FetchTagsParams, Tag, TagVersion } from '@/types'


 export const fetchTags = async (
@@ -28,19 +23,6 @@ export const fetchTags = async (
 	...(order && { order }) } })


-export const fetchNicoTags = async (
-    { name, linkedTag, linkStatus, page, limit, order }: FetchNicoTagsParams,
-): Promise<{ tags:  NicoTag[]
-	     count: number }> =>
-    await apiGet ('/tags/nico', { params: {
-	page,
-	limit,
-	name,
-	linked_tag:  linkedTag,
-	link_status: linkStatus === 'all' ? '' : linkStatus,
-	order } })
-
-
 export const fetchTag = async (id: string): Promise<Tag | null> => {
  try
  {
@@ -1,28 +0,0 @@
-import { useState } from 'react'
-
-import { extractValidationError } from '@/lib/apiErrors'
-
-import type { FieldErrors } from '@/lib/apiErrors'
-
-
-export const useValidationErrors = <T extends string> () => {
-  const [baseErrors, setBaseErrors] = useState<string[]> ([])
-  const [fieldErrors, setFieldErrors] = useState<FieldErrors<T>> ({ })
-
-  const clearValidationErrors = () => {
-    setBaseErrors ([])
-    setFieldErrors ({ })
-  }
-
-  const applyValidationError = (error: unknown): boolean => {
-    const validationError = extractValidationError<T> (error)
-    if (!(validationError))
-      return false
-
-    setBaseErrors (validationError.baseErrors)
-    setFieldErrors (validationError.fieldErrors)
-    return true
-  }
-
-  return { baseErrors, fieldErrors, clearValidationErrors, applyValidationError }
-}
@@ -1,20 +0,0 @@
-import { describe, expect, it } from 'vitest'
-
-import { canEditContent } from '@/lib/users'
-
-import type { UserRole } from '@/types'
-
-const userWithRole = (role: UserRole) => ({ role })
-
-describe ('user permission helpers', () => {
-  it ('allows admins and members to edit content', () => {
-    expect (canEditContent (userWithRole ('admin'))).toBe (true)
-    expect (canEditContent (userWithRole ('member'))).toBe (true)
-  })
-
-  it ('does not allow guests or missing users to edit content', () => {
-    expect (canEditContent (userWithRole ('guest'))).toBe (false)
-    expect (canEditContent (null)).toBe (false)
-    expect (canEditContent (undefined)).toBe (false)
-  })
-})
@@ -1,7 +0,0 @@
-import type { User, UserRole } from '@/types'
-
-const CONTENT_EDITOR_ROLES: readonly UserRole[] = ['admin', 'member']
-
-export const canEditContent = (
-    user: Pick<User, 'role'> | null | undefined,
-): boolean => user != null && CONTENT_EDITOR_ROLES.includes (user.role)
@@ -73,13 +73,13 @@ export const originalCreatedAtString = (
 }


-export const inputClass = (invalid?: boolean, className?: string): string =>
-    cn ('w-full rounded border p-2',
-	(invalid
-	 ? ['border-red-500 bg-red-50 text-red-900',
-	    'placeholder:text-red-300',
-	    'focus:border-red-500 focus:outline-none focus:ring-2 focus:ring-red-200',
-	    'dark:border-red-500 dark:bg-red-950/30 dark:text-red-100']
-	 : ['border-gray-300',
-	    'focus:border-blue-500 focus:outline-none focus:ring-2 focus:ring-blue-200']),
-	className)
+export const msToTime = (ms: number): string => {
+  const totalS = Math.trunc (ms / 1_000)
+  const s = String (totalS % 60)
+  const min = String (Math.trunc (totalS / 60) % 60)
+  const h = Math.trunc (totalS / 3_600)
+
+  return (h > 0
+	  ? `${ h }:${ min.padStart (2, '0') }:${ s.padStart (2, '0') }`
+	  : `${ min }:${ s.padStart (2, '0') }`)
+}
@@ -1,72 +0,0 @@
-import { fireEvent, screen, waitFor } from '@testing-library/react'
-import { Route, Routes } from 'react-router-dom'
-import { beforeEach, describe, expect, it, vi } from 'vitest'
-
-import DeerjikistDetailPage from '@/pages/deerjikists/DeerjikistDetailPage'
-import { buildTag } from '@/test/factories'
-import { renderWithProviders } from '@/test/render'
-
-const tagsApi = vi.hoisted (() => ({
-  fetchDeerjikistsByTag: vi.fn (),
-}))
-
-const api = vi.hoisted (() => ({
-  apiPut:     vi.fn (),
-  isApiError: vi.fn (),
-}))
-
-const toastApi = vi.hoisted (() => ({
-  toast: vi.fn (),
-}))
-
-vi.mock ('@/lib/tags', () => tagsApi)
-vi.mock ('@/lib/api', () => api)
-vi.mock ('@/components/ui/use-toast', () => toastApi)
-
-const renderPage = () =>
-  renderWithProviders (
-      <Routes>
-        <Route path="/tags/:id/deerjikists" element={<DeerjikistDetailPage/>}/>
-      </Routes>,
-      { route: '/tags/7/deerjikists' },
-  )
-
-describe ('DeerjikistDetailPage', () => {
-  beforeEach (() => {
-    vi.clearAllMocks ()
-    api.isApiError.mockReturnValue (false)
-  })
-
-  it ('shows indexed validation errors returned for deerjikist rows', async () => {
-    tagsApi.fetchDeerjikistsByTag.mockResolvedValueOnce ({
-      tag:         buildTag ({ id: 7, name: 'deerjika', category: 'deerjikist' }),
-      deerjikists: [{ platform: null, code: 'abc' }],
-    })
-    api.isApiError.mockReturnValue (true)
-    api.apiPut.mockRejectedValueOnce ({
-      response: {
-        status: 422,
-        data:   {
-          type:        'validation_error',
-          message:     '入力内容を確認してください．',
-          errors:      { 'deerjikists.0.platform': ['プラットフォームを入力してください．'] },
-          base_errors: [],
-        },
-      },
-    })
-
-    renderPage ()
-
-    await screen.findByDisplayValue ('abc')
-    fireEvent.submit (screen.getByRole ('button', { name: '更新' }).closest ('form')!)
-
-    await waitFor (() => {
-      expect (api.apiPut).toHaveBeenCalledWith (
-          '/tags/7/deerjikists',
-          [{ platform: null, code: 'abc' }],
-      )
-    })
-    expect (await screen.findByText ('プラットフォームを入力してください．')).toBeInTheDocument ()
-    expect (screen.getByRole ('combobox')).toHaveAttribute ('aria-invalid', 'true')
-  })
-})
@@ -1,10 +1,10 @@
 import { useQuery, useQueryClient } from '@tanstack/react-query'
 import { useEffect, useMemo, useState } from 'react'
+import { Helmet } from 'react-helmet-async'
 import { useParams } from 'react-router-dom'

 import TagLink from '@/components/TagLink'
-import FieldError from '@/components/common/FieldError'
-import FormField from '@/components/common/FormField'
+import Label from '@/components/common/Label'
 import PageTitle from '@/components/common/PageTitle'
 import MainArea from '@/components/layout/MainArea'
 import { toast } from '@/components/ui/use-toast'
@@ -12,16 +12,12 @@ import { PLATFORM_NAMES, PLATFORMS } from '@/consts'
 import { apiPut } from '@/lib/api'
 import { tagsKeys } from '@/lib/queryKeys'
 import { fetchDeerjikistsByTag } from '@/lib/tags'
-import { cn, inputClass } from '@/lib/utils'
-import { useValidationErrors } from '@/lib/useValidationErrors'
+import { cn } from '@/lib/utils'

 import type { FC, FormEvent } from 'react'

 import type { Deerjikist, Platform } from '@/types'

-type DeerjikistFormField =
-    'deerjikists' | `deerjikists${ number }Platform` | `deerjikists${ number }Code`
-

 const DeerjikistDetailPage: FC = () => {
  const { id } = useParams ()
@@ -36,14 +32,11 @@ const DeerjikistDetailPage: FC = () => {
  const [data, setData] =
      useState<(Omit<Deerjikist, 'platform'> & { platform: Platform | null })[]> ([])
  const [disabled, setDisabled] = useState (true)
-  const { baseErrors, fieldErrors, clearValidationErrors, applyValidationError } =
-      useValidationErrors<DeerjikistFormField> ()

  const qc = useQueryClient ()

  const handleSubmit = async (e: FormEvent) => {
    e.preventDefault ()
-    clearValidationErrors ()

    try
    {
@@ -54,9 +47,8 @@ const DeerjikistDetailPage: FC = () => {

      toast ({ description: '更新しました．' })
    }
-    catch (e)
+    catch
    {
-      applyValidationError (e)
      toast ({ title: '更新失敗', description: '入力内容を確認してください．' })
    }
    finally
@@ -78,6 +70,11 @@ const DeerjikistDetailPage: FC = () => {

  return (
      <MainArea>
+	<Helmet>
+	  <meta name="robots" content="noindex"/>
+	  {tag && <title>{tag.name} | ニジラー情報</title>}
+	</Helmet>
+
 	{(loading || !(tag)) ? 'Loading...' : (
 	    <div className="max-w-xl">
 	      <PageTitle>
@@ -85,9 +82,6 @@ const DeerjikistDetailPage: FC = () => {
 	      </PageTitle>

 	      <form onSubmit={handleSubmit} className="my-4 space-y-2">
-		<FieldError messages={baseErrors}/>
-		<FieldError messages={fieldErrors.deerjikists}/>
-
 		{data.map ((datum, i) => (
 		    <fieldset key={i} className="min-w-0 rounded-lg border border-gray-300
 						 dark:border-gray-700 p-4">
@@ -103,48 +97,40 @@ const DeerjikistDetailPage: FC = () => {
 		      </legend>

 		      {/* プラットフォーム */}
-		      <FormField
-			  label="プラットフォーム"
-			  messages={fieldErrors[`deerjikists${ i }Platform`]}>
-			{({ describedBy, invalid }) => (
-			    <select
-				disabled={disabled}
-				value={datum.platform ?? ''}
-				aria-describedby={describedBy}
-				aria-invalid={invalid}
-				className={inputClass (invalid)}
-				onChange={e => setData (prev => {
-				  const rtn = [...prev]
-				  rtn[i] = { ...rtn[i],
-					     platform: (e.target.value || null) as Platform | null }
-				  return rtn
-				})}>
-			      <option value="">&nbsp;</option>
-			      {PLATFORMS.map (p => (
-				  <option key={p} value={p}>
-				    {PLATFORM_NAMES[p]}
-				  </option>))}
-			    </select>)}
-		      </FormField>
+		      <div>
+			<Label>プラットフォーム</Label>
+			<select
+			    className="w-full border p-2 rounded"
+			    disabled={disabled}
+			    value={datum.platform ?? ''}
+			    onChange={e => setData (prev => {
+			      const rtn = [...prev]
+			      rtn[i] = { ...rtn[i],
+					 platform: (e.target.value || null) as Platform | null }
+			      return rtn
+			    })}>
+			  <option value="">&nbsp;</option>
+			  {PLATFORMS.map (p => (
+			      <option key={p} value={p}>
+				{PLATFORM_NAMES[p]}
+			      </option>))}
+			</select>
+		      </div>

 		      {/* コード */}
-		      <FormField
-			  label="コード"
-			  messages={fieldErrors[`deerjikists${ i }Code`]}>
-			{({ describedBy, invalid }) => (
-			    <input
-				type="text"
-				disabled={disabled}
-				value={datum.code}
-				aria-describedby={describedBy}
-				aria-invalid={invalid}
-				className={inputClass (invalid)}
-				onChange={e => setData (prev => {
-				  const rtn = [...prev]
-				  rtn[i] = { ...rtn[i], code: e.target.value }
-				  return rtn
-				})}/>)}
-		      </FormField>
+		      <div>
+			<Label>コード</Label>
+			<input
+			    type="text"
+			    disabled={disabled}
+			    className="w-full border p-2 rounded"
+			    value={datum.code}
+			    onChange={e => setData (prev => {
+			      const rtn = [...prev]
+			      rtn[i] = { ...rtn[i], code: e.target.value }
+			      return rtn
+			    })}/>
+		      </div>
 		    </fieldset>
 		))}

@@ -4,8 +4,7 @@ import { useParams } from 'react-router-dom'

 import TagLink from '@/components/TagLink'
 import WikiBody from '@/components/WikiBody'
-import FieldError from '@/components/common/FieldError'
-import FormField from '@/components/common/FormField'
+import Label from '@/components/common/Label'
 import PageTitle from '@/components/common/PageTitle'
 import TabGroup, { Tab } from '@/components/common/TabGroup'
 import TagInput from '@/components/common/TagInput'
@@ -14,8 +13,6 @@ import { Button } from '@/components/ui/button'
 import { toast } from '@/components/ui/use-toast'
 import { SITE_TITLE } from '@/config'
 import { apiGet, apiPut } from '@/lib/api'
-import { inputClass } from '@/lib/utils'
-import { useValidationErrors } from '@/lib/useValidationErrors'

 import type { FC } from 'react'

@@ -23,8 +20,6 @@ import type { Material, Tag } from '@/types'

 type MaterialWithTag = Material & { tag: Tag }

-type MaterialFormField = 'tag' | 'file' | 'url'
-

 const MaterialDetailPage: FC = () => {
  const { id } = useParams ()
@@ -36,12 +31,8 @@ const MaterialDetailPage: FC = () => {
  const [sending, setSending] = useState (false)
  const [tag, setTag] = useState ('')
  const [url, setURL] = useState ('')
-  const { baseErrors, fieldErrors, clearValidationErrors, applyValidationError } =
-      useValidationErrors<MaterialFormField> ()

  const handleSubmit = async () => {
-    clearValidationErrors ()
-
    const formData = new FormData
    if (tag.trim ())
      formData.append ('tag', tag)
@@ -57,9 +48,8 @@ const MaterialDetailPage: FC = () => {
      setMaterial (data)
      toast ({ title: '更新成功!' })
    }
-    catch (e)
+    catch
    {
-      applyValidationError (e)
      toast ({ title: '更新失敗……', description: '入力を見直してください．' })
    }
    finally
@@ -128,66 +118,54 @@ const MaterialDetailPage: FC = () => {

 		<Tab name="編輯">
 		  <div className="max-w-wl pt-2 space-y-4">
-		    <FieldError messages={baseErrors}/>
-
 		    {/* タグ */}
-		    <FormField label="タグ" messages={fieldErrors.tag}>
-		      {({ describedBy, invalid }) => (
-			  <TagInput
-			      describedBy={describedBy}
-			      invalid={invalid}
-			      value={tag}
-			      setValue={setTag}/>)}
-		    </FormField>
+		    <div>
+		      <Label>タグ</Label>
+		      <TagInput value={tag} setValue={setTag}/>
+		    </div>

 		    {/* ファイル */}
-		    <FormField label="ファイル" messages={fieldErrors.file}>
-		      {({ describedBy, invalid }) => (
-			  <>
-			    <input
-				type="file"
-				accept="image/*,video/*,audio/*"
-				aria-describedby={describedBy}
-				aria-invalid={invalid}
-				onChange={e => {
-				  const f = e.target.files?.[0]
-				  setFile (f ?? null)
-				  setFilePreview (f ? URL.createObjectURL (f) : '')
-				}}/>
-			    {(file && filePreview) && (
-				(/image\/.*/.test (file.type) && (
-				    <img
-					src={filePreview}
-					alt="preview"
-					className="mt-2 max-h-48 rounded border"/>))
-				|| (/video\/.*/.test (file.type) && (
-				    <video
-					src={filePreview}
-					controls
-					className="mt-2 max-h-48 rounded border"/>))
-				|| (/audio\/.*/.test (file.type) && (
-				    <audio
-					src={filePreview}
-					controls
-					className="mt-2 max-h-48"/>))
-				|| (
-				    <p className="text-red-600 dark:text-red-400">
-				      その形式のファイルには対応していません．
-				    </p>))}
-			  </>)}
-		    </FormField>
+		    <div>
+		      <Label>ファイル</Label>
+		      <input
+			  type="file"
+			  accept="image/*,video/*,audio/*"
+			  onChange={e => {
+			    const f = e.target.files?.[0]
+			    setFile (f ?? null)
+			    setFilePreview (f ? URL.createObjectURL (f) : '')
+			  }}/>
+		      {(file && filePreview) && (
+			  (/image\/.*/.test (file.type) && (
+			      <img
+				  src={filePreview}
+				  alt="preview"
+				  className="mt-2 max-h-48 rounded border"/>))
+			  || (/video\/.*/.test (file.type) && (
+			      <video
+				  src={filePreview}
+				  controls
+				  className="mt-2 max-h-48 rounded border"/>))
+			  || (/audio\/.*/.test (file.type) && (
+			      <audio
+				  src={filePreview}
+				  controls
+				  className="mt-2 max-h-48"/>))
+			  || (
+			      <p className="text-red-600 dark:text-red-400">
+				その形式のファイルには対応していません．
+			      </p>))}
+		    </div>

 		    {/* 参考 URL */}
-		    <FormField label="参考 URL" messages={fieldErrors.url}>
-		      {({ describedBy, invalid }) => (
-			  <input
-			      type="url"
-			      value={url}
-			      onChange={e => setURL (e.target.value)}
-			      aria-describedby={describedBy}
-			      aria-invalid={invalid}
-			      className={inputClass (invalid)}/>)}
-		    </FormField>
+		    <div>
+		      <Label>参考 URL</Label>
+		      <input
+			  type="url"
+			  value={url}
+			  onChange={e => setURL (e.target.value)}
+			  className="w-full border p-2 rounded"/>
+		    </div>

 		    {/* 送信 */}
 		    <Button
@@ -203,4 +181,4 @@ const MaterialDetailPage: FC = () => {
      </MainArea>)
 }

-export default MaterialDetailPage
+export default MaterialDetailPage
@@ -1,13 +1,11 @@
 import { fireEvent, screen, waitFor } from '@testing-library/react'
-import { beforeEach, describe, expect, it, vi } from 'vitest'
+import { describe, expect, it, vi } from 'vitest'

 import MaterialNewPage from '@/pages/materials/MaterialNewPage'
 import { renderWithProviders } from '@/test/render'

 const api = vi.hoisted (() => ({
-  apiGet:     vi.fn (),
-  apiPost:    vi.fn (),
-  isApiError: vi.fn (),
+  apiPost: vi.fn (),
 }))

 const toastApi = vi.hoisted (() => ({
@@ -18,12 +16,6 @@ vi.mock ('@/lib/api', () => api)
 vi.mock ('@/components/ui/use-toast', () => toastApi)

 describe ('MaterialNewPage', () => {
-  beforeEach (() => {
-    vi.clearAllMocks ()
-    api.apiGet.mockResolvedValue ([])
-    api.isApiError.mockReturnValue (false)
-  })
-
  it ('initializes tag from query and submits form data', async () => {
    api.apiPost.mockResolvedValueOnce ({})

@@ -43,30 +35,4 @@ describe ('MaterialNewPage', () => {
    expect (formData.get ('url')).toBe ('https://example.com/ref')
    expect (toastApi.toast).toHaveBeenCalledWith ({ title: '送信成功!' })
  })
-
-  it ('shows validation errors for file and url fields', async () => {
-    api.isApiError.mockReturnValue (true)
-    api.apiPost.mockRejectedValueOnce ({
-      response: {
-        status: 422,
-        data:   {
-          type:        'validation_error',
-          message:     '入力内容を確認してください．',
-          errors:      {
-            file: ['ファイルまたは URL は必須です．'],
-            url:  ['ファイルまたは URL は必須です．'],
-          },
-          base_errors: [],
-        },
-      },
-    })
-
-    renderWithProviders (<MaterialNewPage/>)
-
-    fireEvent.change (screen.getAllByRole ('textbox')[0], { target: { value: '虹夏' } })
-    fireEvent.click (screen.getByRole ('button', { name: '追加' }))
-
-    expect (await screen.findAllByText ('ファイルまたは URL は必須です．')).toHaveLength (2)
-    expect (screen.getAllByRole ('textbox')[1]).toHaveAttribute ('aria-invalid', 'true')
-  })
 })
@@ -2,9 +2,8 @@ import { useState } from 'react'
 import { Helmet } from 'react-helmet-async'
 import { useLocation, useNavigate } from 'react-router-dom'

-import FieldError from '@/components/common/FieldError'
 import Form from '@/components/common/Form'
-import FormField from '@/components/common/FormField'
+import Label from '@/components/common/Label'
 import PageTitle from '@/components/common/PageTitle'
 import TagInput from '@/components/common/TagInput'
 import MainArea from '@/components/layout/MainArea'
@@ -12,13 +11,9 @@ import { Button } from '@/components/ui/button'
 import { toast } from '@/components/ui/use-toast'
 import { SITE_TITLE } from '@/config'
 import { apiPost } from '@/lib/api'
-import { inputClass } from '@/lib/utils'
-import { useValidationErrors } from '@/lib/useValidationErrors'

 import type { FC } from 'react'

-type MaterialFormField = 'tag' | 'file' | 'url'
-

 const MaterialNewPage: FC = () => {
  const location = useLocation ()
@@ -32,12 +27,8 @@ const MaterialNewPage: FC = () => {
  const [sending, setSending] = useState (false)
  const [tag, setTag] = useState (tagQuery)
  const [url, setURL] = useState ('')
-  const { baseErrors, fieldErrors, clearValidationErrors, applyValidationError } =
-      useValidationErrors<MaterialFormField> ()

  const handleSubmit = async () => {
-    clearValidationErrors ()
-
    const formData = new FormData
    if (tag)
      formData.append ('tag', tag)
@@ -53,9 +44,8 @@ const MaterialNewPage: FC = () => {
      toast ({ title: '送信成功!' })
      navigate (`/materials?tag=${ encodeURIComponent (tag) }`)
    }
-    catch (e)
+    catch
    {
-      applyValidationError (e)
      toast ({ title: '送信失敗……', description: '入力を見直してください．' })
    }
    finally
@@ -72,66 +62,55 @@ const MaterialNewPage: FC = () => {

 	<Form>
 	  <PageTitle>素材追加</PageTitle>
-	  <FieldError messages={baseErrors}/>

 	  {/* タグ */}
-	  <FormField label="タグ" messages={fieldErrors.tag}>
-	    {({ describedBy, invalid }) => (
-		<TagInput
-		    describedBy={describedBy}
-		    invalid={invalid}
-		    value={tag}
-		    setValue={setTag}/>)}
-	  </FormField>
+	  <div>
+	    <Label>タグ</Label>
+	    <TagInput value={tag} setValue={setTag}/>
+	  </div>

 	  {/* ファイル */}
-	  <FormField label="ファイル" messages={fieldErrors.file}>
-	    {({ describedBy, invalid }) => (
-		<>
-		  <input
-		      type="file"
-		      accept="image/*,video/*,audio/*"
-		      aria-describedby={describedBy}
-		      aria-invalid={invalid}
-		      onChange={e => {
-			const f = e.target.files?.[0]
-			setFile (f ?? null)
-			setFilePreview (f ? URL.createObjectURL (f) : '')
-		      }}/>
-		  {(file && filePreview) && (
-		      (/image\/.*/.test (file.type) && (
-			  <img
-			      src={filePreview}
-			      alt="preview"
-			      className="mt-2 max-h-48 rounded border"/>))
-		      || (/video\/.*/.test (file.type) && (
-			  <video
-			      src={filePreview}
-			      controls
-			      className="mt-2 max-h-48 rounded border"/>))
-		      || (/audio\/.*/.test (file.type) && (
-			  <audio
-			      src={filePreview}
-			      controls
-			      className="mt-2 max-h-48"/>))
-		      || (
-			  <p className="text-red-600 dark:text-red-400">
-			    その形式のファイルには対応していません．
-			  </p>))}
-		</>)}
-	  </FormField>
+	  <div>
+	    <Label>ファイル</Label>
+	    <input
+		type="file"
+		accept="image/*,video/*,audio/*"
+		onChange={e => {
+		  const f = e.target.files?.[0]
+		  setFile (f ?? null)
+		  setFilePreview (f ? URL.createObjectURL (f) : '')
+		}}/>
+	    {(file && filePreview) && (
+		(/image\/.*/.test (file.type) && (
+		    <img
+			src={filePreview}
+			alt="preview"
+			className="mt-2 max-h-48 rounded border"/>))
+		|| (/video\/.*/.test (file.type) && (
+		    <video
+			src={filePreview}
+			controls
+			className="mt-2 max-h-48 rounded border"/>))
+		|| (/audio\/.*/.test (file.type) && (
+		    <audio
+			src={filePreview}
+			controls
+			className="mt-2 max-h-48"/>))
+		|| (
+		    <p className="text-red-600 dark:text-red-400">
+		      その形式のファイルには対応していません．
+		    </p>))}
+	  </div>

 	  {/* 参考 URL */}
-	  <FormField label="参考 URL" messages={fieldErrors.url}>
-	    {({ describedBy, invalid }) => (
-		<input
-		    type="url"
-		    value={url}
-		    onChange={e => setURL (e.target.value)}
-		    aria-describedby={describedBy}
-		    aria-invalid={invalid}
-		    className={inputClass (invalid)}/>)}
-	  </FormField>
+	  <div>
+	    <Label>参考 URL</Label>
+	    <input
+		type="url"
+		value={url}
+		onChange={e => setURL (e.target.value)}
+		className="w-full border p-2 rounded"/>
+	  </div>

 	  {/* 送信 */}
 	  <Button
@@ -144,4 +123,4 @@ const MaterialNewPage: FC = () => {
      </MainArea>)
 }

-export default MaterialNewPage
+export default MaterialNewPage
@@ -1,7 +1,7 @@
 import { useState } from 'react'
 import { Helmet } from 'react-helmet-async'

-import FormField from '@/components/common/FormField'
+import Label from '@/components/common/Label'
 import PageTitle from '@/components/common/PageTitle'
 import TagInput from '@/components/common/TagInput'
 import MainArea from '@/components/layout/MainArea'
@@ -29,23 +29,23 @@ const MaterialSearchPage: FC = () => {

 	  <form onSubmit={handleSearch} className="space-y-2">
 	    {/* タグ */}
-	    <FormField label="タグ">
-	      {() => (
-		  <TagInput
-		      value={tagName}
-		      setValue={setTagName}/>)}
-	    </FormField>
+	    <div>
+	      <Label>タグ</Label>
+	      <TagInput
+		  value={tagName}
+		  setValue={setTagName}/>
+	    </div>

 	    {/* 親タグ */}
-	    <FormField label="親タグ">
-	      {() => (
-		  <TagInput
-		      value={parentTagName}
-		      setValue={setParentTagName}/>)}
-	    </FormField>
+	    <div>
+	      <Label>親タグ</Label>
+	      <TagInput
+		  value={parentTagName}
+		  setValue={setParentTagName}/>
+	    </div>
 	  </form>
 	</div>
      </MainArea>)
 }

-export default MaterialSearchPage
+export default MaterialSearchPage
@@ -3,6 +3,7 @@ import { motion } from 'framer-motion'
 import { useEffect, useRef, useState } from 'react'
 import { Helmet } from 'react-helmet-async'
 import { useParams } from 'react-router-dom'
+
 import PostEditForm from '@/components/PostEditForm'
 import PostEmbed from '@/components/PostEmbed'
 import PostList from '@/components/PostList'
@@ -15,7 +16,6 @@ import { SITE_TITLE } from '@/config'
 import { isApiError } from '@/lib/api'
 import { fetchPost, toggleViewedFlg } from '@/lib/posts'
 import { postsKeys, tagsKeys } from '@/lib/queryKeys'
-import { canEditContent } from '@/lib/users'
 import { cn } from '@/lib/utils'
 import NotFound from '@/pages/NotFound'
 import ServiceUnavailable from '@/pages/ServiceUnavailable'
@@ -28,7 +28,6 @@ type Props = { user: User | null }


 const PostDetailPage: FC<Props> = ({ user }) => {
-  const editable = canEditContent (user)
  const { id } = useParams ()
  const postId = String (id ?? '')
  const postKey = postsKeys.show (postId)
@@ -165,7 +164,7 @@ const PostDetailPage: FC<Props> = ({ user }) => {
 		     ? <PostList posts={post.related}/>
 		     : 'まだないよ（笑）'}
 		  </Tab>
-		  {editable && (
+		  {['admin', 'member'].some (r => user?.role === r) && (
 		      <Tab name="編輯">
 			<PostEditForm
 			    post={post}
@@ -1,14 +1,13 @@
 import { fireEvent, screen, waitFor } from '@testing-library/react'
-import { beforeEach, describe, expect, it, vi } from 'vitest'
+import { describe, expect, it, vi } from 'vitest'

 import PostNewPage from '@/pages/posts/PostNewPage'
 import { buildUser } from '@/test/factories'
 import { renderWithProviders } from '@/test/render'

 const api = vi.hoisted (() => ({
-  apiGet:     vi.fn (),
-  apiPost:    vi.fn (),
-  isApiError: vi.fn (),
+  apiGet:  vi.fn (),
+  apiPost: vi.fn (),
 }))

 const toastApi = vi.hoisted (() => ({
@@ -19,11 +18,6 @@ vi.mock ('@/lib/api', () => api)
 vi.mock ('@/components/ui/use-toast', () => toastApi)

 describe ('PostNewPage', () => {
-  beforeEach (() => {
-    vi.clearAllMocks ()
-    api.isApiError.mockReturnValue (false)
-  })
-
  it ('blocks guests', () => {
    renderWithProviders (<PostNewPage user={buildUser ({ role: 'guest' })}/>)

@@ -61,36 +55,4 @@ describe ('PostNewPage', () => {
    expect (formData.get ('tags')).toBe ('tag1 tag2')
    expect (toastApi.toast).toHaveBeenCalledWith ({ title: '投稿成功!' })
  })
-
-  it ('shows 422 validation errors for post fields', async () => {
-    api.apiGet.mockResolvedValue ([])
-    api.isApiError.mockReturnValue (true)
-    api.apiPost.mockRejectedValueOnce ({
-      response: {
-        status: 422,
-        data:   {
-          type:        'validation_error',
-          message:     '入力内容を確認してください．',
-          errors:      { tags: ['ニコニコ・タグは直接指定できません．'] },
-          base_errors: ['投稿内容を確認してください．'],
-        },
-      },
-    })
-
-    renderWithProviders (<PostNewPage user={buildUser ({ role: 'member' })}/>)
-
-    const checkboxes = screen.getAllByRole ('checkbox', { name: '自動' })
-    fireEvent.click (checkboxes[0])
-    fireEvent.click (checkboxes[1])
-
-    const textboxes = screen.getAllByRole ('textbox')
-    fireEvent.change (textboxes[0], { target: { value: 'https://example.com/post' } })
-    fireEvent.change (textboxes[1], { target: { value: '投稿タイトル' } })
-    fireEvent.change (textboxes[3], { target: { value: 'nico:nico_tag' } })
-    fireEvent.click (screen.getByRole ('button', { name: '追加' }))
-
-    expect (await screen.findByText ('投稿内容を確認してください．')).toBeInTheDocument ()
-    expect (screen.getByText ('ニコニコ・タグは直接指定できません．')).toBeInTheDocument ()
-    expect (screen.getAllByRole ('textbox')[3]).toHaveAttribute ('aria-invalid', 'true')
-  })
 })
@@ -4,18 +4,14 @@ import { useNavigate } from 'react-router-dom'

 import PostFormTagsArea from '@/components/PostFormTagsArea'
 import PostOriginalCreatedTimeField from '@/components/PostOriginalCreatedTimeField'
-import FieldError from '@/components/common/FieldError'
 import Form from '@/components/common/Form'
-import FormField from '@/components/common/FormField'
+import Label from '@/components/common/Label'
 import PageTitle from '@/components/common/PageTitle'
 import MainArea from '@/components/layout/MainArea'
 import { Button } from '@/components/ui/button'
 import { toast } from '@/components/ui/use-toast'
 import { SITE_TITLE } from '@/config'
 import { apiGet, apiPost } from '@/lib/api'
-import { canEditContent } from '@/lib/users'
-import { inputClass } from '@/lib/utils'
-import { useValidationErrors } from '@/lib/useValidationErrors'
 import Forbidden from '@/pages/Forbidden'

 import type { FC } from 'react'
@@ -24,18 +20,12 @@ import type { User } from '@/types'

 type Props = { user: User | null }

-type PostFormField =
-    'url' | 'title' | 'tags' | 'parentPostIds' | 'originalCreatedAt' | 'thumbnail'
-

 const PostNewPage: FC<Props> = ({ user }) => {
-  const editable = canEditContent (user)
+  const editable = ['admin', 'member'].some (r => user?.role === r)

  const navigate = useNavigate ()

-  const { baseErrors, fieldErrors, clearValidationErrors, applyValidationError } =
-      useValidationErrors<PostFormField> ()
-
  const [originalCreatedBefore, setOriginalCreatedBefore] = useState<string | null> (null)
  const [originalCreatedFrom, setOriginalCreatedFrom] = useState<string | null> (null)
  const [parentPostIds, setParentPostIds] = useState ('')
@@ -53,8 +43,6 @@ const PostNewPage: FC<Props> = ({ user }) => {
  const thumbnailPreviewRef = useRef ('')

  const handleSubmit = async () => {
-    clearValidationErrors ()
-
    const formData = new FormData
    formData.append ('title', title)
    formData.append ('url', url)
@@ -73,9 +61,8 @@ const PostNewPage: FC<Props> = ({ user }) => {
      toast ({ title: '投稿成功!' })
      navigate ('/posts')
    }
-    catch (e)
+    catch
    {
-      applyValidationError (e)
      toast ({ title: '投稿失敗', description: '入力を確認してください。' })
    }
  }
@@ -139,99 +126,85 @@ const PostNewPage: FC<Props> = ({ user }) => {
 	</Helmet>
 	<Form>
 	  <PageTitle>広場に投稿を追加する</PageTitle>
-	  <FieldError messages={baseErrors}/>

 	  {/* URL */}
-	  <FormField label="URL" messages={fieldErrors.url}>
-	    {({ describedBy, invalid }) => (
-		<input type="url"
-		       placeholder="例：https://www.nicovideo.jp/watch/..."
-		       value={url}
-		       onChange={e => setURL (e.target.value)}
-		       aria-describedby={describedBy}
-		       aria-invalid={invalid}
-		       className={inputClass (invalid)}
-		       onBlur={handleURLBlur}/>)}
-	  </FormField>
+	  <div>
+	    <Label>URL</Label>
+	    <input type="url"
+		   placeholder="例：https://www.nicovideo.jp/watch/..."
+		   value={url}
+		   onChange={e => setURL (e.target.value)}
+		   className="w-full border p-2 rounded"
+		   onBlur={handleURLBlur}/>
+	  </div>

 	  {/* タイトル */}
-	  <FormField
-	      checkBox={{
-		  label:    '自動',
-		  checked:  titleAutoFlg,
-		  onChange: ev => setTitleAutoFlg (ev.target.checked)}}
-	      label="タイトル"
-	      messages={fieldErrors.title}>
-	    {({ describedBy, invalid }) => (
-		<input type="text"
-		       aria-describedby={describedBy}
-		       aria-invalid={invalid}
-		       className={inputClass (invalid)}
-		       value={title}
-		       placeholder={titleLoading ? 'Loading...' : ''}
-		       onChange={ev => setTitle (ev.target.value)}
-		       disabled={titleAutoFlg}/>)}
-	  </FormField>
+	  <div>
+	    <Label checkBox={{
+		label:    '自動',
+		checked:  titleAutoFlg,
+		onChange: ev => setTitleAutoFlg (ev.target.checked)}}>
+	      タイトル
+	    </Label>
+	    <input type="text"
+		   className="w-full border rounded p-2"
+		   value={title}
+		   placeholder={titleLoading ? 'Loading...' : ''}
+		   onChange={ev => setTitle (ev.target.value)}
+		   disabled={titleAutoFlg}/>
+	  </div>

 	  {/* サムネール */}
-	  <FormField
-	      checkBox={{
-		  label:    '自動',
-		  checked:  thumbnailAutoFlg,
-		  onChange: ev => setThumbnailAutoFlg (ev.target.checked)}}
-	      label="サムネール"
-	      messages={fieldErrors.thumbnail}>
-	    {({ describedBy, invalid }) => (
-		<>
-		  {thumbnailAutoFlg
-		   ? (thumbnailLoading
-		      ? <p className="text-gray-500 text-sm">Loading...</p>
-		      : !(thumbnailPreview) && (
-			  <p className="text-gray-500 text-sm">
-			    URL から自動取得されます。
-			  </p>))
-		   : (
-		      <input type="file"
-			     accept="image/*"
-			     aria-describedby={describedBy}
-			     aria-invalid={invalid}
-			     onChange={e => {
-			       const file = e.target.files?.[0]
-			       if (file)
-				 {
-				   setThumbnailFile (file)
-				   setThumbnailPreview (URL.createObjectURL (file))
-				 }
-			     }}/>)}
-		  {thumbnailPreview && (
-		      <img src={thumbnailPreview}
-			   alt="preview"
-			   className="mt-2 max-h-48 rounded border"/>)}
-		</>)}
-	  </FormField>
+	  <div>
+	    <Label checkBox={{
+		label:    '自動',
+		checked:  thumbnailAutoFlg,
+		onChange: ev => setThumbnailAutoFlg (ev.target.checked)}}>
+	      サムネール
+	    </Label>
+	    {thumbnailAutoFlg
+	     ? (thumbnailLoading
+		? <p className="text-gray-500 text-sm">Loading...</p>
+		: !(thumbnailPreview) && (
+		    <p className="text-gray-500 text-sm">
+		      URL から自動取得されます。
+		    </p>))
+	     : (
+		<input type="file"
+		       accept="image/*"
+		       onChange={e => {
+			 const file = e.target.files?.[0]
+			 if (file)
+			   {
+			     setThumbnailFile (file)
+			     setThumbnailPreview (URL.createObjectURL (file))
+			   }
+		       }}/>)}
+	    {thumbnailPreview && (
+		<img src={thumbnailPreview}
+		     alt="preview"
+		     className="mt-2 max-h-48 rounded border"/>)}
+	  </div>

 	  {/* 親投稿 */}
-	  <FormField label="親投稿" messages={fieldErrors.parentPostIds}>
-	    {({ describedBy, invalid }) => (
-		<input
-		    type="text"
-		    value={parentPostIds}
-		    onChange={e => setParentPostIds (e.target.value)}
-		    aria-describedby={describedBy}
-		    aria-invalid={invalid}
-		    className={inputClass (invalid)}/>)}
-	  </FormField>
+	  <div>
+	    <Label>親投稿</Label>
+	    <input
+		type="text"
+		value={parentPostIds}
+		onChange={e => setParentPostIds (e.target.value)}
+		className="w-full border p-2 rounded"/>
+	  </div>

 	  {/* タグ */}
-	  <PostFormTagsArea tags={tags} setTags={setTags} errors={fieldErrors.tags}/>
+	  <PostFormTagsArea tags={tags} setTags={setTags}/>

 	  {/* オリジナルの作成日時 */}
 	  <PostOriginalCreatedTimeField
 	      originalCreatedFrom={originalCreatedFrom}
 	      setOriginalCreatedFrom={setOriginalCreatedFrom}
 	      originalCreatedBefore={originalCreatedBefore}
-	      setOriginalCreatedBefore={setOriginalCreatedBefore}
-	      errors={fieldErrors.originalCreatedAt}/>
+	      setOriginalCreatedBefore={setOriginalCreatedBefore}/>

 	  {/* 送信 */}
 	  <Button onClick={handleSubmit}
@@ -8,7 +8,7 @@ import PrefetchLink from '@/components/PrefetchLink'
 import SortHeader from '@/components/SortHeader'
 import TagLink from '@/components/TagLink'
 import DateTimeField from '@/components/common/DateTimeField'
-import FormField from '@/components/common/FormField'
+import Label from '@/components/common/Label'
 import PageTitle from '@/components/common/PageTitle'
 import Pagination from '@/components/common/Pagination'
 import TagInput from '@/components/common/TagInput'
@@ -16,7 +16,7 @@ import MainArea from '@/components/layout/MainArea'
 import { SITE_TITLE } from '@/config'
 import { fetchPosts } from '@/lib/posts'
 import { postsKeys } from '@/lib/queryKeys'
-import { dateString, inputClass, originalCreatedAtString } from '@/lib/utils'
+import { dateString, originalCreatedAtString } from '@/lib/utils'

 import type { FC, FormEvent } from 'react'

@@ -138,33 +138,31 @@ const PostSearchPage: FC = () => {

 	  <form onSubmit={handleSearch} className="space-y-2">
 	    {/* タイトル */}
-	    <FormField label="タイトル">
-	      {({ invalid }) => (
-		  <input
-		      type="text"
-		      value={title}
-		      onChange={e => setTitle (e.target.value)}
-		      className={inputClass (invalid)}/>)}
-	    </FormField>
+	    <div>
+	      <Label>タイトル</Label>
+	      <input
+		  type="text"
+		  value={title}
+		  onChange={e => setTitle (e.target.value)}
+		  className="w-full border p-2 rounded"/>
+	    </div>

 	    {/* URL */}
-	    <FormField label="URL">
-	      {({ invalid }) => (
-		  <input
-		      type="text"
-		      value={url}
-		      onChange={e => setURL (e.target.value)}
-		      className={inputClass (invalid)}/>)}
-	    </FormField>
+	    <div>
+	      <Label>URL</Label>
+	      <input
+		  type="text"
+		  value={url}
+		  onChange={e => setURL (e.target.value)}
+		  className="w-full border p-2 rounded"/>
+	    </div>

 	    {/* タグ */}
-	    <FormField label="タグ">
-	      {() => (
-		  <TagInput
-		      value={tagsStr}
-		      setValue={setTagsStr}/>)}
-	    </FormField>
 	    <div>
+	      <Label>タグ</Label>
+	      <TagInput
+		  value={tagsStr}
+		  setValue={setTagsStr}/>
 	      <fieldset className="w-full my-2">
 		<label>検索区分：</label>
 		<label className="mx-2">
@@ -187,46 +185,40 @@ const PostSearchPage: FC = () => {
 	    </div>

 	    {/* オリジナルの投稿日時 */}
-	    <FormField label="オリジナルの投稿日時">
-	      {() => (
-		  <>
-		    <DateTimeField
-			value={originalCreatedFrom ?? undefined}
-			onChange={setOriginalCreatedFrom}/>
-		    <span className="mx-1">〜</span>
-		    <DateTimeField
-			value={originalCreatedTo ?? undefined}
-			onChange={setOriginalCreatedTo}/>
-		  </>)}
-	    </FormField>
+	    <div>
+	      <Label>オリジナルの投稿日時</Label>
+	      <DateTimeField
+		  value={originalCreatedFrom ?? undefined}
+		  onChange={setOriginalCreatedFrom}/>
+	      <span className="mx-1">〜</span>
+	      <DateTimeField
+		  value={originalCreatedTo ?? undefined}
+		  onChange={setOriginalCreatedTo}/>
+	    </div>

 	    {/* 投稿日時 */}
-	    <FormField label="投稿日時">
-	      {() => (
-		  <>
-		    <DateTimeField
-			value={createdFrom ?? undefined}
-			onChange={setCreatedFrom}/>
-		    <span className="mx-1">〜</span>
-		    <DateTimeField
-			value={createdTo ?? undefined}
-			onChange={setCreatedTo}/>
-		  </>)}
-	    </FormField>
+	    <div>
+	      <Label>投稿日時</Label>
+	      <DateTimeField
+		  value={createdFrom ?? undefined}
+		  onChange={setCreatedFrom}/>
+	      <span className="mx-1">〜</span>
+	      <DateTimeField
+		  value={createdTo ?? undefined}
+		  onChange={setCreatedTo}/>
+	    </div>

 	    {/* 更新日時 */}
-	    <FormField label="更新日時">
-	      {() => (
-		  <>
-		    <DateTimeField
-			value={updatedFrom ?? undefined}
-			onChange={setUpdatedFrom}/>
-		    <span className="mx-1">〜</span>
-		    <DateTimeField
-			value={updatedTo ?? undefined}
-			onChange={setUpdatedTo}/>
-		  </>)}
-	    </FormField>
+	    <div>
+	      <Label>更新日時</Label>
+	      <DateTimeField
+		  value={updatedFrom ?? undefined}
+		  onChange={setUpdatedFrom}/>
+	      <span className="mx-1">〜</span>
+	      <DateTimeField
+		  value={updatedTo ?? undefined}
+		  onChange={setUpdatedTo}/>
+	    </div>

 	    {/* 検索 */}
 	    <div className="py-3">
@@ -1,273 +0,0 @@
-import { fireEvent, screen, waitFor } from '@testing-library/react'
-import { beforeEach, describe, expect, it, vi } from 'vitest'
-
-import NicoTagListPage from '@/pages/tags/NicoTagListPage'
-import { dateString } from '@/lib/utils'
-import { buildTag, buildUser } from '@/test/factories'
-import { renderWithProviders } from '@/test/render'
-
-import type { NicoTag } from '@/types'
-
-const api = vi.hoisted (() => ({
-  apiGet:     vi.fn (),
-  apiPut:     vi.fn (),
-  isApiError: vi.fn (),
-}))
-
-const toastApi = vi.hoisted (() => ({
-  toast: vi.fn (),
-}))
-
-const dialogue = vi.hoisted (() => ({
-  confirm: vi.fn (),
-}))
-
-const scrollIntoView = vi.fn ()
-
-vi.mock ('@/lib/api', () => api)
-vi.mock ('@/components/ui/use-toast', () => toastApi)
-vi.mock ('@/components/dialogues/DialogueProvider', () => ({
-  useDialogue: () => dialogue,
-}))
-
-const buildNicoTag = (values: Partial<NicoTag> = {}): NicoTag => ({
-    ...buildTag (),
-    ...values,
-    category:               'nico',
-    linkedTags:             values.linkedTags ?? [],
-    recentPostTagCreatedAt: values.recentPostTagCreatedAt ?? null,
-})
-
-const renderPage = (route = '/tags/nico') =>
-  renderWithProviders (
-      <NicoTagListPage user={buildUser ({ role: 'member' })}/>,
-      { route },
-  )
-
-describe ('NicoTagListPage', () => {
-  beforeEach (() => {
-    vi.clearAllMocks ()
-    api.isApiError.mockReturnValue (false)
-    dialogue.confirm.mockResolvedValue (true)
-    Element.prototype.scrollIntoView = scrollIntoView
-    scrollIntoView.mockClear ()
-  })
-
-  it ('loads a filtered page from URL search parameters', async () => {
-    api.apiGet.mockResolvedValue ({
-      tags:  [buildNicoTag ({
-        id:                     1,
-        name:                   'nico:linked',
-        createdAt:              '2024-01-02T03:04:05Z',
-        recentPostTagCreatedAt: '2025-01-02T03:04:05Z',
-        updatedAt:              '2026-01-02T03:04:05Z',
-      })],
-      count: 21,
-    })
-
-    renderPage (
-        '/tags/nico?name=linked&linked_tag=destination&link_status=linked'
-	+ '&page=2&order=name:asc',
-    )
-
-    await waitFor (() => {
-      expect (api.apiGet).toHaveBeenCalledWith (
-          '/tags/nico',
-          { params: {
-            page:        2,
-            limit:       20,
-            name:        'linked',
-            linked_tag:  'destination',
-            link_status: 'linked',
-            order:       'name:asc',
-          } },
-      )
-    })
-    expect (await screen.findByText ('21 件')).toBeInTheDocument ()
-    expect (screen.getByLabelText ('前のページ')).toBeInTheDocument ()
-    expect (screen.queryByText ('なし')).not.toBeInTheDocument ()
-    expect (screen.getByText (dateString ('2025-01-02T03:04:05Z'))).toBeInTheDocument ()
-    expect (screen.queryByText (dateString ('2026-01-02T03:04:05Z'))).not.toBeInTheDocument ()
-    expect (screen.getByRole ('link', { name: 'ニコニコタグ ▲' })).toHaveAttribute (
-        'href',
-        expect.stringContaining ('order=name%3Adesc'),
-    )
-    expect (screen.getByRole ('link', { name: '最初に記載された日時' })).toHaveAttribute (
-        'href',
-        expect.stringContaining ('order=created_at%3Adesc'),
-    )
-    expect (screen.getByRole ('link', { name: '最近記載された日時' })).toHaveAttribute (
-        'href',
-        expect.stringContaining ('order=updated_at%3Adesc'),
-    )
-
-    fireEvent.mouseEnter (screen.getByLabelText ('前のページ'))
-    await waitFor (() => {
-      expect (api.apiGet).toHaveBeenLastCalledWith (
-          '/tags/nico',
-          { params: {
-            page:        1,
-            limit:       20,
-            name:        'linked',
-            linked_tag:  'destination',
-            link_status: 'linked',
-            order:       'name:asc',
-          } },
-      )
-    })
-  })
-
-  it ('scrolls to the table when moving between pages', async () => {
-    api.apiGet.mockResolvedValue ({
-      tags:  [buildNicoTag ({ id: 1, name: 'nico:linked' })],
-      count: 21,
-    })
-
-    renderPage ()
-
-    fireEvent.click (await screen.findByLabelText ('次のページ'))
-
-    await waitFor (() => {
-      expect (scrollIntoView).toHaveBeenCalledWith ({ behavior: 'smooth' })
-    })
-  })
-
-  it ('navigates with submitted search conditions', async () => {
-    api.apiGet.mockResolvedValue ({ tags: [], count: 0 })
-    renderPage ()
-
-    fireEvent.change (screen.getByLabelText ('ニコニコタグ'), {
-      target: { value: 'source' },
-    })
-    fireEvent.change (screen.getByLabelText ('連携タグ'), {
-      target: { value: 'destination' },
-    })
-    fireEvent.change (screen.getByLabelText ('連携状態'), {
-      target: { value: 'unlinked' },
-    })
-    fireEvent.submit (screen.getByRole ('button', { name: '検索' }).closest ('form')!)
-
-    await waitFor (() => {
-      expect (api.apiGet).toHaveBeenLastCalledWith (
-          '/tags/nico',
-          { params: expect.objectContaining ({
-            page:        1,
-            name:        'source',
-            linked_tag:  'destination',
-            link_status: 'unlinked',
-          }) },
-      )
-    })
-  })
-
-  it ('updates links from a tag card', async () => {
-    api.apiGet
-      .mockResolvedValueOnce ({
-        tags:  [buildNicoTag ({ id: 7, name: 'nico:source' })],
-        count: 1,
-      })
-      .mockResolvedValueOnce ({
-        tags: [
-          buildNicoTag ({
-            id:         7,
-            name:       'nico:source',
-            linkedTags: [buildTag ({ id: 8, name: '連携先' })],
-          }),
-        ],
-        count: 1,
-      })
-    api.apiPut.mockResolvedValueOnce ([buildTag ({ id: 8, name: '連携先' })])
-
-    renderPage ()
-
-    fireEvent.click (await screen.findByRole ('button', { name: '編集' }))
-    fireEvent.change (screen.getByLabelText ('連携する広場タグ'), {
-      target: { value: '連携先' },
-    })
-    fireEvent.click (screen.getByRole ('button', { name: '保存' }))
-
-    await waitFor (() => {
-      expect (api.apiPut).toHaveBeenCalledWith (
-          '/tags/nico/7',
-          expect.any (FormData),
-          { headers: { 'Content-Type': 'multipart/form-data' } },
-      )
-    })
-    expect (await screen.findByText ('1 件')).toBeInTheDocument ()
-  })
-
-  it ('asks before discarding changes when editing another tag', async () => {
-    api.apiGet.mockResolvedValueOnce ({
-      tags: [
-        buildNicoTag ({ id: 1, name: 'nico:first' }),
-        buildNicoTag ({ id: 2, name: 'nico:second' }),
-      ],
-      count: 2,
-    })
-
-    renderPage ()
-    dialogue.confirm.mockResolvedValueOnce (false)
-
-    const editButtons = await screen.findAllByRole ('button', { name: '編集' })
-    fireEvent.click (editButtons[0])
-    fireEvent.change (screen.getByLabelText ('連携する広場タグ'), {
-      target: { value: '入力中' },
-    })
-    fireEvent.click (screen.getAllByRole ('button', { name: '編集' })[0])
-
-    await waitFor (() => {
-      expect (dialogue.confirm).toHaveBeenCalledWith ({
-        title:       '編集中の内容を破棄しますか?',
-        confirmText: '破棄',
-        variant:     'danger',
-      })
-    })
-    expect (screen.getAllByLabelText ('連携する広場タグ')).toHaveLength (1)
-    expect (screen.getByLabelText ('連携する広場タグ')).toHaveValue ('入力中')
-  })
-
-  it ('switches editing rows without confirmation when unchanged', async () => {
-    api.apiGet.mockResolvedValueOnce ({
-      tags: [
-        buildNicoTag ({ id: 1, name: 'nico:first' }),
-        buildNicoTag ({ id: 2, name: 'nico:second' }),
-      ],
-      count: 2,
-    })
-
-    renderPage ()
-
-    const editButtons = await screen.findAllByRole ('button', { name: '編集' })
-    fireEvent.click (editButtons[0])
-    fireEvent.click (screen.getAllByRole ('button', { name: '編集' })[0])
-
-    expect (dialogue.confirm).not.toHaveBeenCalled ()
-    expect (screen.getAllByLabelText ('連携する広場タグ')).toHaveLength (1)
-  })
-
-  it ('shows tags field validation errors inside the edited card', async () => {
-    api.apiGet.mockResolvedValueOnce ({
-      tags:  [buildNicoTag ({ id: 7, name: 'nico:source' })],
-      count: 1,
-    })
-    api.isApiError.mockReturnValue (true)
-    api.apiPut.mockRejectedValueOnce ({
-      response: {
-        status: 422,
-        data:   {
-          type:        'validation_error',
-          errors:      { tags: ['タグ名を確認してください．'] },
-          base_errors: [],
-        },
-      },
-    })
-
-    renderPage ()
-
-    fireEvent.click (await screen.findByRole ('button', { name: '編集' }))
-    fireEvent.click (screen.getByRole ('button', { name: '保存' }))
-
-    expect (await screen.findByText ('タグ名を確認してください．')).toBeInTheDocument ()
-    expect (screen.getByLabelText ('連携する広場タグ')).toHaveAttribute ('aria-invalid', 'true')
-  })
-})
@@ -1,179 +1,104 @@
-import { useQuery, useQueryClient } from '@tanstack/react-query'
-import { Check, LoaderCircle, Pencil, X } from 'lucide-react'
-import { useEffect, useMemo, useState } from 'react'
+import type { FC } from 'react'
+
+import { useCallback, useEffect, useRef, useState } from 'react'
 import { Helmet } from 'react-helmet-async'
-import { useLocation, useNavigate } from 'react-router-dom'

 import TagLink from '@/components/TagLink'
-import SortHeader from '@/components/SortHeader'
-import FieldError from '@/components/common/FieldError'
-import FormField from '@/components/common/FormField'
 import PageTitle from '@/components/common/PageTitle'
-import Pagination from '@/components/common/Pagination'
 import TextArea from '@/components/common/TextArea'
-import { useDialogue } from '@/components/dialogues/DialogueProvider'
 import MainArea from '@/components/layout/MainArea'
 import { toast } from '@/components/ui/use-toast'
 import { SITE_TITLE } from '@/config'
-import { apiPut } from '@/lib/api'
-import { extractValidationError } from '@/lib/apiErrors'
-import { tagsKeys } from '@/lib/queryKeys'
-import { fetchNicoTags } from '@/lib/tags'
-import { cn, dateString, inputClass } from '@/lib/utils'
-import { canEditContent } from '@/lib/users'
+import { apiGet, apiPut } from '@/lib/api'

-import type { FC, FormEvent } from 'react'
+import type { NicoTag, Tag, User } from '@/types'

-import type { FetchNicoTagsOrder, FetchNicoTagsOrderField, NicoTag, Tag, User } from '@/types'
-
-type LinkStatus = 'all' | 'linked' | 'unlinked'
 type Props = { user: User | null }


-const setIf = (qs: URLSearchParams, key: string, value: string) => {
-  const trimmed = value.trim ()
-  if (trimmed)
-    qs.set (key, trimmed)
-}
-
-
 const NicoTagListPage: FC<Props> = ({ user }) => {
-  const dialogue = useDialogue ()
-  const location = useLocation ()
-  const navigate = useNavigate ()
-  const queryClient = useQueryClient ()
-  const query = useMemo (() => new URLSearchParams (location.search), [location.search])
+  const [cursor, setCursor] = useState ('')
+  const [editing, setEditing] = useState<{ [key: number]: boolean }> ({ })
+  const [loading, setLoading] = useState (false)
+  const [nicoTags, setNicoTags] = useState<NicoTag[]> ([])
+  const [rawTags, setRawTags] = useState<{ [key: number]: string }> ({ })

-  const page = Number (query.get ('page') ?? 1)
-  const limit = Number (query.get ('limit') ?? 20)
-  const qName = query.get ('name') ?? ''
-  const qLinkedTag = query.get ('linked_tag') ?? ''
-  const qLinkStatus = (query.get ('link_status') || 'all') as LinkStatus
-  const order = (query.get ('order') || 'updated_at:desc') as FetchNicoTagsOrder
+  const loaderRef = useRef<HTMLDivElement | null> (null)

-  const [editingId, setEditingId] = useState<number | null> (null)
-  const [errorsByTagId, setErrorsByTagId] = useState<Record<number, string[]>> ({ })
-  const [linkStatus, setLinkStatus] = useState<LinkStatus> ('all')
-  const [linkedTag, setLinkedTag] = useState ('')
-  const [name, setName] = useState ('')
-  const [rawTags, setRawTags] = useState<Record<number, string>> ({ })
-  const [savingId, setSavingId] = useState<number | null> (null)
+  const memberFlg = ['admin', 'member'].some (r => user?.role === r)

-  const keys = {
-      name: qName, linkedTag: qLinkedTag, linkStatus: qLinkStatus, page, limit, order }
-  const { data, isError, isLoading: loading } = useQuery ({
-      queryKey: tagsKeys.nicoIndex (keys),
-      queryFn:  () => fetchNicoTags (keys) })
-  const nicoTags = data?.tags ?? []
-  const count = data?.count ?? 0
+  const applyLoadedTags = useCallback ((data: { tags: NicoTag[]; nextCursor: string },
+					withCursor: boolean) => {
+    setNicoTags (tags => [...(withCursor ? tags : []), ...data.tags])
+    setCursor (data.nextCursor)

-  const editable = canEditContent (user)
-  const totalPages = Math.ceil (count / limit)
+    const newEditing = Object.fromEntries (data.tags.map (t => [t.id, false]))
+    setEditing (editing => ({ ...editing, ...newEditing }))

-  const handleSearch = (e: FormEvent) => {
-    e.preventDefault ()
+    const newRawTags = Object.fromEntries (
+	data.tags.map (t => [t.id, t.linkedTags.map (lt => lt.name).join (' ')]))
+    setRawTags (rawTags => ({ ...rawTags, ...newRawTags }))
+  }, [])

-    const qs = new URLSearchParams ()
-    setIf (qs, 'name', name)
-    setIf (qs, 'linked_tag', linkedTag)
-    if (linkStatus !== 'all')
-      qs.set ('link_status', linkStatus)
-    qs.set ('page', '1')
-    qs.set ('limit', String (limit))
-    qs.set ('order', order)
-    navigate (`${ location.pathname }?${ qs.toString () }`)
+  const loadInitial = useCallback (async () => {
+    setLoading (true)
+
+    const data = await apiGet<{ tags: NicoTag[]; nextCursor: string }> ('/tags/nico')
+    applyLoadedTags (data, false)
+
+    setLoading (false)
+  }, [applyLoadedTags])
+
+  const loadMore = useCallback (async () => {
+    setLoading (true)
+
+    const data = await apiGet<{ tags: NicoTag[]; nextCursor: string }> (
+	'/tags/nico', { params: { cursor } })
+    applyLoadedTags (data, true)
+
+    setLoading (false)
+  }, [applyLoadedTags, cursor])
+
+  const handleEdit = async (id: number) => {
+    if (editing[id])
+      {
+	const formData = new FormData
+	formData.append ('tags', rawTags[id])
+
+	const data = await apiPut<Tag[]> (`/tags/nico/${ id }`, formData,
+				    { headers: { 'Content-Type': 'multipart/form-data' } })
+	setNicoTags (nicoTags => {
+	  nicoTags.find (t => t.id === id)!.linkedTags = data
+	  return [...nicoTags]
+	})
+	setRawTags (rawTags => ({ ...rawTags, [id]: data.map (t => t.name).join (' ') }))
+
+	toast ({ title: '更新しました．' })
+      }
+
+    setEditing (editing => ({ ...editing, [id]: !(editing[id]) }))
  }

-  const defaultDirection = {
-      name:       'asc',
-      created_at: 'desc',
-      updated_at: 'desc',
-  } as const
+  useEffect(() => {
+    const observer = new IntersectionObserver (entries => {
+      if (entries[0].isIntersecting && !(loading) && cursor)
+	loadMore ()
+    }, { threshold: 1 })

-  const beginEdit = async (tag: NicoTag) => {
-    const editingTag = nicoTags.find (tag => tag.id === editingId)
-    const editingValue = editingTag?.linkedTags.map (tag => tag.name).join (' ') ?? ''
-    const editingChanged = editingId != null && rawTags[editingId] !== editingValue
+    const target = loaderRef.current
+    if (target)
+      observer.observe (target)

-    if (editingId != null && editingId !== tag.id && editingChanged
-	&& !(await dialogue.confirm ({
-	  title:       '編集中の内容を破棄しますか?',
-	  confirmText: '破棄',
-	  variant:     'danger',
-	})))
-      return
-
-    setEditingId (tag.id)
-    setRawTags (rawTags => ({
-	...rawTags,
-	[tag.id]: tag.linkedTags.map (linkedTag => linkedTag.name).join (' '),
-    }))
-    setErrorsByTagId (errors => ({ ...errors, [tag.id]: [] }))
-  }
-
-  const cancelEdit = (tag: NicoTag) => {
-    setEditingId (null)
-    setRawTags (rawTags => ({
-	...rawTags,
-	[tag.id]: tag.linkedTags.map (linkedTag => linkedTag.name).join (' '),
-    }))
-    setErrorsByTagId (errors => ({ ...errors, [tag.id]: [] }))
-  }
-
-  const saveLinks = async (id: number) => {
-    const formData = new FormData
-    formData.append ('tags', rawTags[id] ?? '')
-    setSavingId (id)
-
-    try
-    {
-      await apiPut<Tag[]> (`/tags/nico/${ id }`, formData,
-			   { headers: { 'Content-Type': 'multipart/form-data' } })
-      setErrorsByTagId (errors => ({ ...errors, [id]: [] }))
-      setEditingId (null)
-      await queryClient.invalidateQueries ({ queryKey: tagsKeys.nicoRoot })
-      toast ({ description: '連携を更新しました．' })
+    return () => {
+      if (target)
+	observer.unobserve (target)
    }
-    catch (e)
-    {
-      const validationError = extractValidationError<'tags'> (e)
-      setErrorsByTagId (errors => ({
-	  ...errors,
-	  [id]: validationError?.fieldErrors.tags
-	      ?? validationError?.baseErrors
-	      ?? ['更新できませんでした．'],
-      }))
-      toast ({ title: '更新失敗', description: '入力内容を確認してください．' })
-    }
-    finally
-    {
-      setSavingId (null)
-    }
-  }
+  }, [cursor, loadMore, loading])

  useEffect (() => {
-    setName (qName)
-    setLinkedTag (qLinkedTag)
-    setLinkStatus (qLinkStatus)
-    setEditingId (null)
-
-    document.querySelector ('table')?.scrollIntoView ({ behavior: 'smooth' })
-  }, [location.search, qLinkedTag, qLinkStatus, qName])
-
-  useEffect (() => {
-    if (!(data))
-      return
-
-    setRawTags (Object.fromEntries (data.tags.map (tag => [
-      tag.id,
-      tag.linkedTags.map (linkedTag => linkedTag.name).join (' '),
-    ])))
-  }, [data])
-
-  useEffect (() => {
-    if (isError)
-      toast ({ title: '読込失敗', description: 'ニコニコ連携を読み込めませんでした．' })
-  }, [isError])
+    setNicoTags ([])
+    loadInitial ()
+  }, [loadInitial])

  return (
      <MainArea>
@@ -183,201 +108,58 @@ const NicoTagListPage: FC<Props> = ({ user }) => {

 	<div className="max-w-xl">
 	  <PageTitle>ニコニコ連携</PageTitle>
-	  <p className="mb-4 text-sm text-gray-600 dark:text-gray-300">
-	    ニコニコタグを広場のタグへ結び付けます．
-	  </p>
-
-	  <form onSubmit={handleSearch} className="space-y-2">
-	    <FormField label="ニコニコタグ">
-	      {({ invalid }) => (
-		  <input
-		      type="text"
-		      aria-label="ニコニコタグ"
-		      value={name}
-		      onChange={e => setName (e.target.value)}
-		      className={inputClass (invalid)}/>)}
-	    </FormField>
-
-	    <FormField label="連携タグ">
-	      {({ invalid }) => (
-		  <input
-		      type="text"
-		      aria-label="連携タグ"
-		      value={linkedTag}
-		      onChange={e => setLinkedTag (e.target.value)}
-		      className={inputClass (invalid)}/>)}
-	    </FormField>
-
-	    <FormField label="連携状態">
-	      {({ invalid }) => (
-		  <select
-		      aria-label="連携状態"
-		      value={linkStatus}
-		      onChange={e => setLinkStatus (e.target.value as LinkStatus)}
-		      className={inputClass (invalid)}>
-		    <option value="all">すべて</option>
-		    <option value="linked">連携済み</option>
-		    <option value="unlinked">未連携</option>
-		  </select>)}
-	    </FormField>
-
-	    <div className="py-3">
-	      <button
-		  type="submit"
-		  className="rounded bg-blue-500 px-4 py-2 text-white">
-		検索
-	      </button>
-	    </div>
-	  </form>
 	</div>

-	{loading
-	 ? 'Loading...'
-	 : (
-	    <div className="mt-6">
-	      <div className="mb-3 flex items-baseline justify-between gap-4">
-		<h2 className="text-lg font-bold">検索結果</h2>
-		<span className="text-sm text-gray-500 dark:text-gray-400">{count} 件</span>
-	      </div>
-
-	      {nicoTags.length > 0
-	       ? (
-		  <div className="overflow-x-auto">
-		    <table className="w-full min-w-[800px] table-fixed border-collapse">
-		      <colgroup>
-			<col className="w-64"/>
-			<col className="w-[48rem]"/>
-			<col className="w-56"/>
-			<col className="w-56"/>
-			{editable && <col className="w-24"/>}
-		      </colgroup>
-		      <thead className="border-b-2 border-black dark:border-white">
-			<tr>
-			  <th className="p-2 text-left whitespace-nowrap">
-			    <SortHeader<FetchNicoTagsOrderField>
-				by="name"
-				label="ニコニコタグ"
-				currentOrder={order}
-				defaultDirection={defaultDirection}/>
-			  </th>
-			  <th className="p-2 text-left">連携タグ</th>
-			  <th className="p-2 text-left whitespace-nowrap">
-			    <SortHeader<FetchNicoTagsOrderField>
-				by="created_at"
-				label="最初に記載された日時"
-				currentOrder={order}
-				defaultDirection={defaultDirection}/>
-			  </th>
-			  <th className="p-2 text-left whitespace-nowrap">
-			    <SortHeader<FetchNicoTagsOrderField>
-				by="updated_at"
-				label="最近記載された日時"
-				currentOrder={order}
-				defaultDirection={defaultDirection}/>
-			  </th>
-			  {editable && <th className="p-2"></th>}
-			</tr>
-		      </thead>
-		      <tbody>
-			{nicoTags.map (tag => {
-			  const isEditing = editingId === tag.id
-
-			  return [
-			    <tr
-				key={tag.id}
-				className={cn (
-				    'border-b border-gray-200 dark:border-gray-700',
-				    isEditing
-				    ? 'bg-rose-50 dark:bg-rose-950/30'
-				    : 'even:bg-gray-100 dark:even:bg-gray-800')}>
-			      <td className="p-2 align-top font-semibold">
-				<TagLink tag={tag} withWiki={false} withCount={false}/>
-			      </td>
-			      <td className="p-2 align-top">
-				{tag.linkedTags.map ((linkedTag, i) => (
-				    <span key={linkedTag.id}>
-				      {i > 0 && ' '}
-				      <TagLink
-					  tag={linkedTag}
-					  linkFlg={false}
-					  withCount={false}/>
-				    </span>))}
-			      </td>
-			      <td className="p-2 align-top whitespace-nowrap">
-				{dateString (tag.createdAt)}
-			      </td>
-			      <td className="p-2 align-top whitespace-nowrap">
-				{tag.recentPostTagCreatedAt && dateString (tag.recentPostTagCreatedAt)}
-			      </td>
-			      {editable && (
-				  <td className="p-2 text-right align-top">
-				    {!(isEditing) && (
-					<button
-					    type="button"
-					    onClick={() => beginEdit (tag)}
-					    className="inline-flex items-center gap-1 text-sm text-blue-700
-						       hover:underline dark:text-blue-300">
-					  <Pencil className="size-3.5"/>
-					  編集
-					</button>)}
-				  </td>)}
-			    </tr>,
-			    isEditing && (
-				<tr key={`${ tag.id }-edit`}
-				    className="border-b border-rose-200 bg-rose-50 dark:border-rose-900
-					       dark:bg-rose-950/30">
-				  <td colSpan={editable ? 5 : 4} className="p-3">
-				    <div className="space-y-2">
-				      <label htmlFor={`nico-links-${ tag.id }`}
-					     className="block text-sm font-semibold">
-					連携する広場タグ
-				      </label>
-				      <TextArea
-					  id={`nico-links-${ tag.id }`}
-					  value={rawTags[tag.id] ?? ''}
-					  invalid={(errorsByTagId[tag.id] ?? []).length > 0}
-					  className="min-h-24 resize-y"
-					  placeholder="タグ名を空白または改行で区切って入力"
-					  onChange={e => setRawTags (rawTags => ({
-					      ...rawTags,
-					      [tag.id]: e.target.value,
-					  }))}/>
-				      <FieldError messages={errorsByTagId[tag.id]}/>
-				      <div className="flex justify-end gap-2">
-					<button
-					    type="button"
-					    disabled={savingId === tag.id}
-					    onClick={() => cancelEdit (tag)}
-					    className="inline-flex items-center gap-1 rounded border
-						       border-gray-300 px-3 py-1.5 text-sm
-						       disabled:opacity-50 dark:border-gray-700">
-					  <X className="size-3.5"/>
-					  取消
-					</button>
-					<button
-					    type="button"
-					    disabled={savingId === tag.id}
-					    onClick={() => saveLinks (tag.id)}
-					    className="inline-flex items-center gap-1 rounded bg-rose-700
-						       px-3 py-1.5 text-sm text-white disabled:opacity-50">
-					  {savingId === tag.id
-					   ? <LoaderCircle className="size-3.5 animate-spin"/>
-					   : <Check className="size-3.5"/>}
-					  保存
-					</button>
-				      </div>
-				    </div>
-				  </td>
-				</tr>),
-			  ]
-			})}
-		      </tbody>
-		    </table>
-		  </div>)
-	       : <p>結果ないよ（笑）</p>}
-
-	      <Pagination page={page} totalPages={totalPages}/>
-	    </div>)}
+	<div className="mt-4">
+	  {nicoTags.length > 0 && (
+	      <table className="table-auto w-full border-collapse mb-4">
+		<thead className="border-b-2 border-black dark:border-white">
+		  <tr>
+		    <th className="p-2 text-left">ニコニコタグ</th>
+		    <th className="p-2 text-left">連携タグ</th>
+		    {memberFlg && <th></th>}
+		  </tr>
+		</thead>
+		<tbody>
+		  {nicoTags.map ((tag, i) => (
+		      <tr key={i} className="even:bg-gray-100 dark:even:bg-gray-700">
+			<td className="p-2">
+			  <TagLink tag={tag} withWiki={false} withCount={false}/>
+			</td>
+			<td className="p-2">
+			  {editing[tag.id]
+			   ? (
+			      <TextArea value={rawTags[tag.id]} onChange={ev => {
+				setRawTags (rawTags => ({ ...rawTags, [tag.id]: ev.target.value }))
+			      }}/>)
+			   : tag.linkedTags.map((lt, j) => (
+			      <span key={j} className="mr-2">
+				<TagLink tag={lt}
+					 linkFlg={false}
+					 withCount={false}/>
+			      </span>))}
+			</td>
+			{memberFlg && (
+			    <td className="p-2">
+			      <a href="#" onClick={ev => {
+				ev.preventDefault ()
+				handleEdit (tag.id)
+			      }}>
+			        {editing[tag.id]
+				 ? (
+				    <span className="text-red-600 hover:text-red-400
+						     dark:text-red-300 dark:hover:text-red-100">
+				      更新
+				    </span>)
+				 : <span>編輯</span>}
+			      </a>
+			    </td>)}
+		      </tr>))}
+		</tbody>
+	      </table>)}
+	  {loading && 'Loading...'}
+	  <div ref={loaderRef} className="h-12"></div>
+	</div>
      </MainArea>)
 }

@@ -1,6 +1,6 @@
 import { fireEvent, screen, waitFor } from '@testing-library/react'
 import { Route, Routes } from 'react-router-dom'
-import { beforeEach, describe, expect, it, vi } from 'vitest'
+import { describe, expect, it, vi } from 'vitest'

 import TagDetailPage from '@/pages/tags/TagDetailPage'
 import { buildTag } from '@/test/factories'
@@ -11,8 +11,7 @@ const tagsApi = vi.hoisted (() => ({
 }))

 const api = vi.hoisted (() => ({
-  apiPut:     vi.fn (),
-  isApiError: vi.fn (),
+  apiPut: vi.fn (),
 }))

 const toastApi = vi.hoisted (() => ({
@@ -29,14 +28,9 @@ const renderPage = () =>
        <Route path="/tags/:id" element={<TagDetailPage/>}/>
      </Routes>,
      { route: '/tags/7' },
-)
+  )

 describe ('TagDetailPage', () => {
-  beforeEach (() => {
-    vi.clearAllMocks ()
-    api.isApiError.mockReturnValue (false)
-  })
-
  it ('loads and displays an editable tag', async () => {
    tagsApi.fetchTag.mockResolvedValueOnce (
        buildTag ({ id: 7, name: '虹夏', category: 'character', aliases: ['drums'] }),
@@ -74,28 +68,4 @@ describe ('TagDetailPage', () => {

    expect (await screen.findByRole ('button', { name: '更新' })).toBeDisabled ()
  })
-
-  it ('shows validation errors returned for tag fields', async () => {
-    tagsApi.fetchTag.mockResolvedValueOnce (buildTag ({ id: 7, name: 'old' }))
-    api.isApiError.mockReturnValue (true)
-    api.apiPut.mockRejectedValueOnce ({
-      response: {
-        status: 422,
-        data:   {
-          type:        'validation_error',
-          message:     '入力内容を確認してください．',
-          errors:      { category: ['ニコタグは変更できません．'] },
-          base_errors: [],
-        },
-      },
-    })
-
-    renderPage ()
-
-    await screen.findByDisplayValue ('old')
-    fireEvent.submit (screen.getByRole ('button', { name: '更新' }).closest ('form')!)
-
-    expect (await screen.findByText ('ニコタグは変更できません．')).toBeInTheDocument ()
-    expect (screen.getByRole ('combobox')).toHaveAttribute ('aria-invalid', 'true')
-  })
 })
@@ -3,8 +3,7 @@ import { useEffect, useState } from 'react'
 import { useParams } from 'react-router-dom'

 import TagLink from '@/components/TagLink'
-import FieldError from '@/components/common/FieldError'
-import FormField from '@/components/common/FormField'
+import Label from '@/components/common/Label'
 import PageTitle from '@/components/common/PageTitle'
 import MainArea from '@/components/layout/MainArea'
 import { toast } from '@/components/ui/use-toast'
@@ -12,15 +11,12 @@ import { CATEGORIES, CATEGORY_NAMES } from '@/consts'
 import { apiPut } from '@/lib/api'
 import { postsKeys, tagsKeys } from '@/lib/queryKeys'
 import { fetchTag } from '@/lib/tags'
-import { cn, inputClass } from '@/lib/utils'
-import { useValidationErrors } from '@/lib/useValidationErrors'
+import { cn } from '@/lib/utils'

 import type { FC, FormEvent } from 'react'

 import type { Category, Tag } from '@/types'

-type TagFormField = 'name' | 'category' | 'aliases' | 'parentTags'
-

 const TagDetailPage: FC = () => {
  const { id } = useParams ()
@@ -36,14 +32,11 @@ const TagDetailPage: FC = () => {
  const [aliases, setAliases] = useState ('')
  const [parentTags, setParentTags] = useState ('')
  const [disabled, setDisabled] = useState (true)
-  const { baseErrors, fieldErrors, clearValidationErrors, applyValidationError } =
-      useValidationErrors<TagFormField> ()

  const qc = useQueryClient ()

  const handleSubmit = async (e: FormEvent) => {
    e.preventDefault ()
-    clearValidationErrors ()

    const formData = new FormData
    formData.append ('name', name)
@@ -64,9 +57,8 @@ const TagDetailPage: FC = () => {
      qc.invalidateQueries ({ queryKey: tagsKeys.root })
      toast ({ description: '更新しました．' })
    }
-    catch (e)
+    catch
    {
-      applyValidationError (e)
      toast ({ description: '更新に失敗しました．' })
    }
  }
@@ -97,73 +89,57 @@ const TagDetailPage: FC = () => {
 	      </PageTitle>

 	      <form onSubmit={handleSubmit} className="my-4 space-y-2">
-		<FieldError messages={baseErrors}/>
-
 		{/* 名称 */}
-		<FormField label="名称" messages={fieldErrors.name}>
-		  {({ describedBy, invalid }) => (
-		      <>
-			{/* TODO: 補完に対応させる */}
-			<input
-			    type="text"
-			    disabled={disabled}
-			    value={name}
-			    onChange={e => setName (e.target.value)}
-			    aria-describedby={describedBy}
-			    aria-invalid={invalid}
-			    className={inputClass (invalid)}/>
-		      </>)}
-		</FormField>
+		<div>
+		  <Label>名称</Label>
+		  {/* TODO: 補完に対応させる */}
+		  <input
+		      type="text"
+		      disabled={disabled}
+		      value={name}
+		      onChange={e => setName (e.target.value)}
+		      className="w-full border p-2 rounded"/>
+		</div>

 		{/* カテゴリ */}
-		<FormField label="カテゴリ" messages={fieldErrors.category}>
-		  {({ describedBy, invalid }) => (
+		<div>
+		  <Label>カテゴリ</Label>
 		  <select
 		      disabled={disabled}
 		      value={category ?? ''}
 		      onChange={e => setCategory(e.target.value as Category)}
-		      aria-describedby={describedBy}
-		      aria-invalid={invalid}
-		      className={inputClass (invalid)}>
+		      className="w-full border p-2 rounded">
 		    {CATEGORIES.filter (cat => tag.category === 'nico' || cat !== 'nico')
 			       .map (cat => (
 			<option key={cat} value={cat}>
 			  {CATEGORY_NAMES[cat]}
 			</option>))}
-		  </select>)}
-		</FormField>
+		  </select>
+		</div>

 		{/* 別名 */}
-		<FormField label="別名" messages={fieldErrors.aliases}>
-		  {({ describedBy, invalid }) => (
-		      <>
-			{/* TODO: 補完に対応させる */}
-			<input
-			    type="text"
-			    disabled={disabled}
-			    value={aliases}
-			    onChange={e => setAliases (e.target.value)}
-			    aria-describedby={describedBy}
-			    aria-invalid={invalid}
-			    className={inputClass (invalid)}/>
-		      </>)}
-		</FormField>
+		<div>
+		  <Label>別名</Label>
+		  {/* TODO: 補完に対応させる */}
+		  <input
+		      type="text"
+		      disabled={disabled}
+		      value={aliases}
+		      onChange={e => setAliases (e.target.value)}
+		      className="w-full border p-2 rounded"/>
+		</div>

 		{/* 上位タグ */}
-		<FormField label="上位タグ" messages={fieldErrors.parentTags}>
-		  {({ describedBy, invalid }) => (
-		      <>
-			{/* TODO: 補完に対応させる */}
-			<input
-			    type="text"
-			    disabled={disabled}
-			    value={parentTags}
-			    onChange={e => setParentTags (e.target.value)}
-			    aria-describedby={describedBy}
-			    aria-invalid={invalid}
-			    className={inputClass (invalid)}/>
-		      </>)}
-		</FormField>
+		<div>
+		  <Label>上位タグ</Label>
+		  {/* TODO: 補完に対応させる */}
+		  <input
+		      type="text"
+		      disabled={disabled}
+		      value={parentTags}
+		      onChange={e => setParentTags (e.target.value)}
+		      className="w-full border p-2 rounded"/>
+		</div>

 		<div className="py-3">
 		  <button
@@ -7,7 +7,7 @@ import PrefetchLink from '@/components/PrefetchLink'
 import SortHeader from '@/components/SortHeader'
 import TagLink from '@/components/TagLink'
 import DateTimeField from '@/components/common/DateTimeField'
-import FormField from '@/components/common/FormField'
+import Label from '@/components/common/Label'
 import PageTitle from '@/components/common/PageTitle'
 import Pagination from '@/components/common/Pagination'
 import MainArea from '@/components/layout/MainArea'
@@ -15,7 +15,7 @@ import { SITE_TITLE } from '@/config'
 import { CATEGORIES, CATEGORY_NAMES } from '@/consts'
 import { tagsKeys } from '@/lib/queryKeys'
 import { fetchTags } from '@/lib/tags'
-import { dateString, inputClass } from '@/lib/utils'
+import { dateString } from '@/lib/utils'

 import type { FC, FormEvent } from 'react'

@@ -127,79 +127,71 @@ const TagListPage: FC = () => {

 	  <form onSubmit={handleSearch} className="space-y-2">
 	    {/* 名前 */}
-	    <FormField label="名前">
-	      {({ invalid }) => (
-		  <input
-		      type="text"
-		      value={name}
-		      onChange={e => setName (e.target.value)}
-		      className={inputClass (invalid)}/>)}
-	    </FormField>
+	    <div>
+	      <Label>名前</Label>
+	      <input
+		  type="text"
+		  value={name}
+		  onChange={e => setName (e.target.value)}
+		  className="w-full border p-2 rounded"/>
+	    </div>

 	    {/* カテゴリ */}
-	    <FormField label="カテゴリ">
-	      {({ invalid }) => (
-		  <select
-		      value={category ?? ''}
-		      onChange={e => setCategory((e.target.value || null) as Category | null)}
-		      className={inputClass (invalid)}>
-		    <option value="">&nbsp;</option>
-		    {CATEGORIES.map (cat => (
-			<option key={cat} value={cat}>
-			  {CATEGORY_NAMES[cat]}
-			</option>))}
-		  </select>)}
-	    </FormField>
+	    <div>
+	      <Label>カテゴリ</Label>
+	      <select
+		  value={category ?? ''}
+		  onChange={e => setCategory((e.target.value || null) as Category | null)}
+		  className="w-full border p-2 rounded">
+		<option value="">&nbsp;</option>
+		{CATEGORIES.map (cat => (
+		    <option key={cat} value={cat}>
+		      {CATEGORY_NAMES[cat]}
+		    </option>))}
+	      </select>
+	    </div>

 	    {/* 広場の投稿数 */}
-	    <FormField label="広場の投稿数">
-	      {({ invalid }) => (
-		  <>
-		    <input
-			type="number"
-			min="0"
-			value={postCountGTE < 0 ? 0 : String (postCountGTE)}
-			onChange={e => setPostCountGTE (Number (e.target.value || 0))}
-			className={inputClass (invalid, 'w-auto')}/>
-		    <span className="mx-1">〜</span>
-		    <input
-			type="number"
-			min="0"
-			value={postCountLTE == null ? '' : String (postCountLTE)}
-			onChange={e => setPostCountLTE (e.target.value
-							? Number (e.target.value)
-							: null)}
-			className={inputClass (invalid, 'w-auto')}/>
-		  </>)}
-	    </FormField>
+	    <div>
+	      <Label>広場の投稿数</Label>
+	      <input
+		  type="number"
+		  min="0"
+		  value={postCountGTE < 0 ? 0 : String (postCountGTE)}
+		  onChange={e => setPostCountGTE (Number (e.target.value || 0))}
+		  className="border rounded p-2"/>
+	      <span className="mx-1">〜</span>
+	      <input
+		  type="number"
+		  min="0"
+		  value={postCountLTE == null ? '' : String (postCountLTE)}
+		  onChange={e => setPostCountLTE (e.target.value ? Number (e.target.value) : null)}
+		  className="border rounded p-2"/>
+	    </div>

 	    {/* はじめて記載された日時 */}
-	    <FormField label="はじめて記載された日時">
-	      {() => (
-		  <>
-		    <DateTimeField
-			value={createdFrom ?? undefined}
-			onChange={setCreatedFrom}/>
-		    <span className="mx-1">〜</span>
-		    <DateTimeField
-			value={createdTo ?? undefined}
-			onChange={setCreatedTo}/>
-		  </>)}
-	    </FormField>
+	    <div>
+	      <Label>はじめて記載された日時</Label>
+	      <DateTimeField
+		  value={createdFrom ?? undefined}
+		  onChange={setCreatedFrom}/>
+	      <span className="mx-1">〜</span>
+	      <DateTimeField
+		  value={createdTo ?? undefined}
+		  onChange={setCreatedTo}/>
+	    </div>

 	    {/* 定義の更新日時 */}
-	    <FormField label="定義の更新日時">
-	      {() => (
-		  <>
-		    <DateTimeField
-			value={updatedFrom ?? undefined}
-			onChange={setUpdatedFrom}/>
-		    <span className="mx-1">〜</span>
-		    <DateTimeField
-			value={updatedTo ?? undefined}
-			onChange={setUpdatedTo}/>
-		  </>)}
-	    </FormField>
+	    <div>
+	      <Label>定義の更新日時</Label>
+	      <DateTimeField
+		  value={updatedFrom ?? undefined}
+		  onChange={setUpdatedFrom}/>
+	      <span className="mx-1">〜</span>
+	      <DateTimeField
+		  value={updatedTo ?? undefined}
+		  onChange={setUpdatedTo}/>
+	    </div>

 	    <div className="py-3">
 	      <button
@@ -6,14 +6,12 @@ import ErrorScreen from '@/components/ErrorScreen'
 import PostEmbed from '@/components/PostEmbed'
 import PrefetchLink from '@/components/PrefetchLink'
 import TagDetailSidebar from '@/components/TagDetailSidebar'
-import FieldError from '@/components/common/FieldError'
 import MainArea from '@/components/layout/MainArea'
 import SidebarComponent from '@/components/layout/SidebarComponent'
 import { SITE_TITLE } from '@/config'
 import { apiGet, apiPatch, apiPost, apiPut, isApiError } from '@/lib/api'
 import { fetchPost } from '@/lib/posts'
-import { dateString, inputClass } from '@/lib/utils'
-import { useValidationErrors } from '@/lib/useValidationErrors'
+import { dateString } from '@/lib/utils'

 import type { FC } from 'react'

@@ -29,8 +27,6 @@ type TheatreInfo = {
    postStartedAt:  string | null
    watchingUsers:  { id: number; name: string }[] }

-type TheatreCommentField = 'content'
-
 const INITIAL_THEATRE_INFO =
    { hostFlg: false,
      postId: null,
@@ -57,8 +53,6 @@ const TheatreDetailPage: FC = () => {
  const [theatreInfo, setTheatreInfo] = useState<TheatreInfo> (INITIAL_THEATRE_INFO)
  const [post, setPost] = useState<Post | null> (null)
  const [videoLength, setVideoLength] = useState (0)
-  const { fieldErrors, clearValidationErrors, applyValidationError } =
-      useValidationErrors<TheatreCommentField> ()

  useEffect (() => {
    loadingRef.current = loading
@@ -290,28 +284,22 @@ const TheatreDetailPage: FC = () => {
 		try
 		{
 		  setSending (true)
-		  clearValidationErrors ()
 		  await apiPost (`/theatres/${ id }/comments`, { content })
 		  setContent ('')
 		  commentsRef.current?.scrollTo ({ top: 0, behavior: 'smooth' })
 		}
-		catch (error)
-		{
-		  applyValidationError (error)
-		}
 		finally
 		{
 		  setSending (false)
 		}
 	      }}>
 	    <input
-		className={inputClass ((fieldErrors.content ?? []).length > 0)}
+		className="w-full p-2 border rounded"
 		type="text"
 		placeholder="ここにコメントを入力"
 		value={content}
 		onChange={e => setContent (e.target.value)}
 		disabled={sending}/>
-	    <FieldError messages={fieldErrors.content}/>

 	    <div
 		ref={commentsRef}
@@ -1,13 +1,12 @@
 import { fireEvent, screen, waitFor } from '@testing-library/react'
-import { beforeEach, describe, expect, it, vi } from 'vitest'
+import { describe, expect, it, vi } from 'vitest'

 import SettingPage from '@/pages/users/SettingPage'
 import { buildUser } from '@/test/factories'
 import { renderWithProviders } from '@/test/render'

 const api = vi.hoisted (() => ({
-  apiPut:     vi.fn (),
-  isApiError: vi.fn (),
+  apiPut: vi.fn (),
 }))

 const toastApi = vi.hoisted (() => ({
@@ -24,11 +23,6 @@ vi.mock ('@/components/users/InheritDialogue', () => ({
 }))

 describe ('SettingPage', () => {
-  beforeEach (() => {
-    vi.clearAllMocks ()
-    api.isApiError.mockReturnValue (false)
-  })
-
  it ('shows loading when user is absent', () => {
    renderWithProviders (<SettingPage user={null} setUser={vi.fn ()}/>)

@@ -57,28 +51,4 @@ describe ('SettingPage', () => {
    expect (setUser).toHaveBeenCalled ()
    expect (toastApi.toast).toHaveBeenCalledWith ({ title: '設定を更新しました．' })
  })
-
-  it ('shows validation errors returned for the name field', async () => {
-    const user = buildUser ({ id: 11, name: 'old' })
-    api.isApiError.mockReturnValue (true)
-    api.apiPut.mockRejectedValueOnce ({
-      response: {
-        status: 422,
-        data:   {
-          type:        'validation_error',
-          message:     '入力内容を確認してください．',
-          errors:      { name: ['名前は必須です．'] },
-          base_errors: [],
-        },
-      },
-    })
-
-    renderWithProviders (<SettingPage user={user} setUser={vi.fn ()}/>)
-
-    fireEvent.change (screen.getByRole ('textbox'), { target: { value: '' } })
-    fireEvent.click (screen.getByRole ('button', { name: '更新' }))
-
-    expect (await screen.findByText ('名前は必須です．')).toBeInTheDocument ()
-    expect (screen.getByRole ('textbox')).toHaveAttribute ('aria-invalid', 'true')
-  })
 })
@@ -3,9 +3,7 @@ import type { FC } from 'react'
 import { useEffect, useState } from 'react'
 import { Helmet } from 'react-helmet-async'

-import FieldError from '@/components/common/FieldError'
 import Form from '@/components/common/Form'
-import FormField from '@/components/common/FormField'
 import Label from '@/components/common/Label'
 import PageTitle from '@/components/common/PageTitle'
 import MainArea from '@/components/layout/MainArea'
@@ -15,30 +13,22 @@ import { Button } from '@/components/ui/button'
 import { toast } from '@/components/ui/use-toast'
 import { SITE_TITLE } from '@/config'
 import { apiPut } from '@/lib/api'
-import { inputClass } from '@/lib/utils'
-import { useValidationErrors } from '@/lib/useValidationErrors'

 import type { User } from '@/types'

 type Props = { user:    User | null
 	       setUser: React.Dispatch<React.SetStateAction<User | null>> }

-type UserFormField = 'name'
-

 const SettingPage: FC<Props> = ({ user, setUser }) => {
  const [name, setName] = useState ('')
  const [userCodeVsbl, setUserCodeVsbl] = useState (false)
  const [inheritVsbl, setInheritVsbl] = useState (false)
-  const { baseErrors, fieldErrors, clearValidationErrors, applyValidationError } =
-      useValidationErrors<UserFormField> ()

  const handleSubmit = async () => {
    if (!(user))
      return

-    clearValidationErrors ()
-
    const formData = new FormData
    formData.append ('name', name)

@@ -50,9 +40,8 @@ const SettingPage: FC<Props> = ({ user, setUser }) => {
      setUser (user => ({ ...user, ...data }))
      toast ({ title: '設定を更新しました．' })
    }
-    catch (e)
+    catch
    {
-      applyValidationError (e)
      toast ({ title: 'しっぱい……' })
    }
  }
@@ -76,16 +65,11 @@ const SettingPage: FC<Props> = ({ user, setUser }) => {

 	  {user ? (
 	      <>
-		<FieldError messages={baseErrors}/>
-
 		{/* 名前 */}
-		<FormField label="表示名" messages={fieldErrors.name}>
-		  {({ describedBy, invalid }) => (
-		      <>
+		<div>
+		  <Label>表示名</Label>
 		  <input type="text"
-			 aria-describedby={describedBy}
-			 aria-invalid={invalid}
-			 className={inputClass (invalid)}
+			 className="w-full border rounded p-2"
 			 value={name}
 			 placeholder="名もなきニジラー"
 			 onChange={ev => setName (ev.target.value)}/>
@@ -93,8 +77,7 @@ const SettingPage: FC<Props> = ({ user, setUser }) => {
 		      <p className="mt-1 text-sm text-red-500">
 			名前が未設定のアカウントは 30 日間アクセスしないと削除されます!!!!
 		      </p>)}
-		      </>)}
-		</FormField>
+		</div>

 		{/* 送信 */}
 		<Button onClick={handleSubmit}
@@ -5,16 +5,11 @@ import { Helmet } from 'react-helmet-async'
 import MdEditor from 'react-markdown-editor-lite'
 import { useParams, useNavigate } from 'react-router-dom'

-import FieldError from '@/components/common/FieldError'
-import FormField from '@/components/common/FormField'
 import MainArea from '@/components/layout/MainArea'
 import { toast } from '@/components/ui/use-toast'
 import { SITE_TITLE } from '@/config'
 import { apiGet, apiPut } from '@/lib/api'
 import { wikiKeys } from '@/lib/queryKeys'
-import { canEditContent } from '@/lib/users'
-import { inputClass } from '@/lib/utils'
-import { useValidationErrors } from '@/lib/useValidationErrors'
 import Forbidden from '@/pages/Forbidden'

 import 'react-markdown-editor-lite/lib/index.css'
@@ -27,11 +22,9 @@ const mdParser = new MarkdownIt

 type Props = { user: User | null }

-type WikiFormField = 'title' | 'body'
-

 const WikiEditPage: FC<Props> = ({ user }) => {
-  const editable = canEditContent (user)
+  const editable = ['admin', 'member'].some (r => user?.role === r)

  const { id } = useParams ()

@@ -42,12 +35,8 @@ const WikiEditPage: FC<Props> = ({ user }) => {
  const [body, setBody] = useState ('')
  const [loading, setLoading] = useState (true)
  const [title, setTitle] = useState ('')
-  const { baseErrors, fieldErrors, clearValidationErrors, applyValidationError } =
-      useValidationErrors<WikiFormField> ()

  const handleSubmit = async () => {
-    clearValidationErrors ()
-
    const formData = new FormData ()
    formData.append ('title', title)
    formData.append ('body', body)
@@ -62,9 +51,8 @@ const WikiEditPage: FC<Props> = ({ user }) => {
      toast ({ title: '投稿成功!' })
      navigate (`/wiki/${ title }`)
    }
-    catch (e)
+    catch
    {
-      applyValidationError (e)
      toast ({ title: '投稿失敗', description: '入力を確認してください。' })
    }
  }
@@ -95,28 +83,24 @@ const WikiEditPage: FC<Props> = ({ user }) => {

 	  {loading ? 'Loading...' : (
 	      <>
-		<FieldError messages={baseErrors}/>
-
 		{/* タイトル */}
 		{/* TODO: タグ補完 */}
-		<FormField label="タイトル" messages={fieldErrors.title}>
-		  {({ describedBy, invalid }) => (
-		      <input type="text"
-			     value={title}
-			     onChange={e => setTitle (e.target.value)}
-			     aria-describedby={describedBy}
-			     aria-invalid={invalid}
-			     className={inputClass (invalid)}/>)}
-		</FormField>
+		<div>
+		  <label className="block font-semibold mb-1">タイトル</label>
+		  <input type="text"
+			 value={title}
+			 onChange={e => setTitle (e.target.value)}
+			 className="w-full border p-2 rounded"/>
+		</div>

 		{/* 本文 */}
-		<FormField label="本文" messages={fieldErrors.body}>
-		  {() => (
-		      <MdEditor value={body}
-				style={{ height: '500px' }}
-				renderHTML={text => mdParser.render (text)}
-				onChange={({ text }) => setBody (text)}/>)}
-		</FormField>
+		<div>
+		  <label className="block font-semibold mb-1">本文</label>
+		  <MdEditor value={body}
+			    style={{ height: '500px' }}
+			    renderHTML={text => mdParser.render (text)}
+			    onChange={({ text }) => setBody (text)}/>
+		</div>

 		{/* 送信 */}
 		<button onClick={handleSubmit}
@@ -6,15 +6,10 @@ import { Helmet } from 'react-helmet-async'
 import MdEditor from 'react-markdown-editor-lite'
 import { useLocation, useNavigate } from 'react-router-dom'

-import FieldError from '@/components/common/FieldError'
-import FormField from '@/components/common/FormField'
 import MainArea from '@/components/layout/MainArea'
 import { toast } from '@/components/ui/use-toast'
 import { SITE_TITLE } from '@/config'
 import { apiPost } from '@/lib/api'
-import { canEditContent } from '@/lib/users'
-import { inputClass } from '@/lib/utils'
-import { useValidationErrors } from '@/lib/useValidationErrors'
 import Forbidden from '@/pages/Forbidden'

 import 'react-markdown-editor-lite/lib/index.css'
@@ -25,11 +20,9 @@ const mdParser = new MarkdownIt

 type Props = { user: User | null }

-type WikiFormField = 'title' | 'body'
-

 const WikiNewPage: FC<Props> = ({ user }) => {
-  const editable = canEditContent (user)
+  const editable = ['admin', 'member'].some (r => user?.role === r)

  const location = useLocation ()
  const navigate = useNavigate ()
@@ -39,12 +32,8 @@ const WikiNewPage: FC<Props> = ({ user }) => {

  const [title, setTitle] = useState (titleQuery)
  const [body, setBody] = useState ('')
-  const { baseErrors, fieldErrors, clearValidationErrors, applyValidationError } =
-      useValidationErrors<WikiFormField> ()

  const handleSubmit = async () => {
-    clearValidationErrors ()
-
    const formData = new FormData
    formData.append ('title', title)
    formData.append ('body', body)
@@ -56,9 +45,8 @@ const WikiNewPage: FC<Props> = ({ user }) => {
      toast ({ title: '投稿成功!' })
      navigate (`/wiki/${ data.title }`)
    }
-    catch (e)
+    catch
    {
-      applyValidationError (e)
      toast ({ title: '投稿失敗', description: '入力を確認してください。' })
    }
  }
@@ -73,28 +61,25 @@ const WikiNewPage: FC<Props> = ({ user }) => {
 	</Helmet>
 	<div className="max-w-xl mx-auto p-4 space-y-4">
 	  <h1 className="text-2xl font-bold mb-2">新規 Wiki ページ</h1>
-	  <FieldError messages={baseErrors}/>

 	  {/* タイトル */}
 	  {/* TODO: タグ補完 */}
-	  <FormField label="タイトル" messages={fieldErrors.title}>
-	    {({ describedBy, invalid }) => (
-		<input type="text"
-		       value={title}
-		       onChange={e => setTitle (e.target.value)}
-		       aria-describedby={describedBy}
-		       aria-invalid={invalid}
-		       className={inputClass (invalid)}/>)}
-	  </FormField>
+	  <div>
+	    <label className="block font-semibold mb-1">タイトル</label>
+	    <input type="text"
+		   value={title}
+		   onChange={e => setTitle (e.target.value)}
+		   className="w-full border p-2 rounded"/>
+	  </div>

 	  {/* 本文 */}
-	  <FormField label="本文" messages={fieldErrors.body}>
-	    {() => (
-		<MdEditor value={body}
-			  style={{ height: '500px' }}
-			  renderHTML={text => mdParser.render (text)}
-			  onChange={({ text }) => setBody (text)}/>)}
-	  </FormField>
+	  <div>
+	    <label className="block font-semibold mb-1">本文</label>
+	    <MdEditor value={body}
+		      style={{ height: '500px' }}
+		      renderHTML={text => mdParser.render (text)}
+		      onChange={({ text }) => setBody (text)}/>
+	  </div>

 	  {/* 送信 */}
 	  <button onClick={handleSubmit}
@@ -2,12 +2,11 @@ import { useEffect, useState } from 'react'
 import { Helmet } from 'react-helmet-async'

 import PrefetchLink from '@/components/PrefetchLink'
-import FormField from '@/components/common/FormField'
 import PageTitle from '@/components/common/PageTitle'
 import MainArea from '@/components/layout/MainArea'
 import { SITE_TITLE } from '@/config'
 import { apiGet } from '@/lib/api'
-import { dateString, inputClass } from '@/lib/utils'
+import { dateString } from '@/lib/utils'

 import type { FormEvent , FC } from 'react'

@@ -44,22 +43,22 @@ const WikiSearchPage: FC = () => {
 	  <PageTitle>Wiki</PageTitle>
 	  <form onSubmit={handleSearch} className="space-y-2">
 	    {/* タイトル */}
-	    <FormField label="タイトル">
-	      {({ invalid }) => (
-		  <input type="text"
-			 value={title}
-			 onChange={e => setTitle (e.target.value)}
-			 className={inputClass (invalid)}/>)}
-	    </FormField>
+	    <div>
+	      <label>タイトル：</label><br />
+	      <input type="text"
+		     value={title}
+		     onChange={e => setTitle (e.target.value)}
+		     className="border p-1 w-full" />
+	    </div>

 	    {/* 内容 */}
-	    <FormField label="内容">
-	      {({ invalid }) => (
-		  <input type="text"
-			 value={text}
-			 onChange={e => setText (e.target.value)}
-			 className={inputClass (invalid)}/>)}
-	    </FormField>
+	    <div>
+	      <label>内容：</label><br />
+	      <input type="text"
+		     value={text}
+		     onChange={e => setText (e.target.value)}
+		     className="border p-1 w-full" />
+	    </div>

 	    {/* 検索 */}
 	    <div className="py-3">
@@ -1,6 +1,6 @@
-import type { Material, Post, Tag, User, WikiPage } from '@/types'
+import type { Material, Post, TagWithSections, User, WikiPage } from '@/types'

-export const buildTag = (overrides: Partial<Tag> = {}): Tag => ({
+export const buildTag = (overrides: Partial<TagWithSections> = {}): TagWithSections => ({
  id:             1,
  name:           'テストタグ',
  category:       'general',
@@ -13,6 +13,8 @@ export const buildTag = (overrides: Partial<Tag> = {}): Tag => ({
  materialId:     null,
  hasDeerjikists: false,
  matchedAlias:   null,
+  sections:       [],
+  children:       [],
  ...overrides,
 })

@@ -52,18 +52,6 @@ export type FetchTagsParams = {
    limit:        number
    order:        FetchTagsOrder }

-export type FetchNicoTagsParams = {
-    name:       string
-    linkedTag:  string
-    linkStatus: 'all' | 'linked' | 'unlinked'
-    page:       number
-    limit:      number
-    order:      FetchNicoTagsOrder }
-
-export type FetchNicoTagsOrder = `${ FetchNicoTagsOrderField }:${ 'asc' | 'desc' }`
-
-export type FetchNicoTagsOrderField = 'name' | 'created_at' | 'updated_at'
-
 export type Material = {
    id:             number
    tag:            Tag
@@ -95,9 +83,8 @@ export type MenuVisibleItem = {
    subMenu:  SubMenuItem[] }

 export type NicoTag = Tag & {
-    category:               'nico'
-    linkedTags:             Tag[]
-    recentPostTagCreatedAt: string | null }
+    category:   'nico'
+    linkedTags: Tag[] }

 export type NiconicoMetadata = {
    currentTime:            number
@@ -139,7 +126,7 @@ export type Post = {
    title:                  string | null
    thumbnail:              string | null
    thumbnailBase:          string | null
-    tags:                   Tag[]
+    tags:                   TagWithSections[]
    parentPosts?:           Post[]
    childPosts?:            Post[]
    siblingPosts?:          Record<`${ number }`, Post[]>
@@ -200,7 +187,6 @@ export type Tag = {
    hasWiki:        boolean
    materialId:     number | null
    hasDeerjikists: boolean
-    children?:      Tag[]
    matchedAlias?:  string | null }

 export type TagVersion = {
@@ -214,6 +200,10 @@ export type TagVersion = {
    createdAt:              string
    createdByUser:          { id: number; name: string | null } | null }

+export type TagWithSections = Tag & { sections: { beginMs:  number
+						  endMs:    number }[]
+			              children: TagWithSections[] }
+
 export type Theatre = {
    id:             number
    name:           string | null
作成者	SHA1	メッセージ	日付
みてるぞ	7e89fb286a	#351	2026-05-23 07:21:15 +09:00
みてるぞ	7fcfc8b8aa	#351	2026-05-23 03:50:54 +09:00
みてるぞ	7b6b24b9c5	#351	2026-05-22 03:29:18 +09:00