#268

Reviewed-on: #397
Co-authored-by: miteruzo <miteruzo@naver.com>
Co-committed-by: miteruzo <miteruzo@naver.com>

AGENTS.md

@@ -362,6 +362,37 @@ const value =
 - Do not use a leading semicolon for expression statements such as
   `;([...]).forEach(...)`; rewrite the expression to avoid ASI hazards
   explicitly, for example with `void`.
+- Do not insert `void` mechanically before ordinary event-handler or callback
+  calls merely because the callee returns a `Promise`. If the surrounding code
+  already uses a plain expression statement such as
+  `onClick={() => requestActiveTab ('theme')}`, preserve that style unless a
+  local rule or type requirement truly forces `void`. Adding unnecessary
+  `void` is a medium-severity style violation.
+- When fixing formatting, never change operator binding, evaluation order,
+  tuple/comma behaviour, or any other expression structure. A formatting pass
+  that changes how `!==`, `??`, `?:`, `&&`, `||`, or `,` binds is a capital
+  offence.
+- In TypeScript and TSX, do not mechanically verticalise short call tails,
+  short object literals, or short callback bodies that already fit the local
+  line-length and delimiter rules. Expanding compact local code without a
+  readability need is a minor style violation.
+- In TypeScript and TSX, treat short object literals, short returned objects,
+  short typed object shapes, and short function-call object arguments as
+  compact associative syntax by default. If they fit locally, keep the opening
+  `{` on the same line as the first property and keep the closing `}` on the
+  same line as the final property. Do not explode them into vertical
+  Prettier-style blocks without a concrete readability or line-length reason.
+- In TypeScript and TSX, when a compact associative form is broken across two
+  lines, keep the opening `{` with the first property and the closing `}` with
+  the final property. A shape like `{\n    key: value,\n}` is wrong even when
+  line length would permit it.
+- In TypeScript and TSX, when a short call such as `apiGet<...> (...)`,
+  `apiPatch<...> (...)`, `setState (...)`, `updateClientSettings (...)`, or
+  `window.dispatchEvent (...)` already fits within the local style, do not
+  add extra vertical layers around the object argument or callback body.
+- In TypeScript and TSX, after editing a file, inspect the file tail and
+  remove meaningless blank lines before `export default` or the end of file.
+  A stray empty line before `export default` is a minor style offence.
 - Use correct British English spelling for new identifiers, filenames,
   component names, helper names, comments, and developer-facing prose unless
   editing an already established American-English API that must keep its
@@ -380,6 +411,168 @@ const value =
 - For this repository, prefer names such as `BehaviourSettingsSection.tsx`, not
   `BehaviorSettingsSection.tsx`.
 
+### Additional style offences and penalties
+
+Use this section for recurrent failure modes that are easy to miss when
+applying the delimiter rules mechanically.
+
+#### Unnecessary `void` before ordinary callbacks
+
+Bad:
+
+```ts
+onClick={() => void requestActiveTab ('theme')}
+```
+
+Good:
+
+```ts
+onClick={() => requestActiveTab ('theme')}
+```
+
+Penalty: medium-severity offence. The code still works, but it pollutes the
+local style and usually signals that the edit was made mechanically rather than
+by reading the surrounding code.
+
+#### Formatting that changes expression structure
+
+Bad:
+
+```ts
+const hasUnsavedChanges =
+    serialiseThemeDraft (draftThemeSlots)
+    !== (serialiseThemeDraft (savedThemeSlots),
+	 draftActiveThemeMode !== savedThemeMode)
+```
+
+Good:
+
+```ts
+const hasUnsavedChanges =
+    serialiseThemeDraft (draftThemeSlots)
+    !== serialiseThemeDraft (savedThemeSlots)
+    || draftThemeMode !== savedThemeMode
+```
+
+Penalty: capital offence. Formatting must never corrupt the meaning of an
+expression.
+
+#### Mechanical vertical expansion of compact local code
+
+Bad:
+
+```ts
+const nextState = {
+    open,
+    activeTab }
+
+setDirtyStates (
+    current => ({
+	current,
+	key:  value }),
+)
+```
+
+Good:
+
+```ts
+const nextState = { open, activeTab }
+
+setDirtyStates (
+    current => ({
+	current,
+	key:  value }))
+```
+
+Penalty: minor offence when semantics stay intact. It is not necessarily
+broken, but it ignores the repository's compact associative style.
+
+#### Prettier-style exploded object literals that should stay compact
+
+Bad:
+
+```ts
+const next = {
+    enabled: keyboard?.enabled !== false,
+    bindings: normaliseKeyboardBindings (keyboard?.bindings),
+}
+```
+
+Good:
+
+```ts
+const next = {
+    enabled: keyboard?.enabled !== false,
+    bindings: normaliseKeyboardBindings (keyboard?.bindings) }
+```
+
+Also good when short enough:
+
+```ts
+const next = { enabled: keyboard?.enabled !== false,
+	       bindings: normaliseKeyboardBindings (keyboard?.bindings) }
+```
+
+Rule: for compact associative syntax, keep `{` with the first property and `}`
+with the final property unless line length truly forces a different shape.
+Do not mechanically apply the common Prettier block form.
+Penalty: medium-severity offence. The code still runs, but it violates a core
+repository formatting habit that must be preserved consistently.
+
+#### Exploded object arguments inside short calls
+
+Bad:
+
+```ts
+updateClientSettings (settings => ({
+    ...settings,
+    keyboard: next,
+}))
+```
+
+Good:
+
+```ts
+updateClientSettings (settings => ({
+    ...settings,
+    keyboard: next }))
+```
+
+Rule: a call-expression closing `)` must not drift onto its own line, and a
+short object argument should not be exploded more than necessary. Keep the
+callback's returned object compact when it fits.
+Penalty: medium-severity offence. This usually means the edit was formatted
+mechanically instead of by reading the local style.
+
+#### Stray blank line before `export default`
+
+Bad:
+
+```ts
+const Component: FC = () => {
+  return <div/>
+}
+
+
+export default Component
+```
+
+Good:
+
+```ts
+const Component: FC = () => {
+  return <div/>
+}
+
+export default Component
+```
+
+Rule: do not leave an extra empty line between the last top-level declaration
+and `export default` unless some surrounding file structure genuinely requires
+visual separation.
+Penalty: minor offence. It is small, but it is easy to avoid and should not
+recur.
+
 ### Frontend delimiter decision table
 
 Use this table before accepting any edited TypeScript or TSX hunk. The table is
@@ -412,6 +605,7 @@ import { Button, Card } from '@/components/ui'
 Rule: named-binding `}` is associative-array-style syntax. It must not be alone
 at the beginning of a line. Prefer keeping `{` with the first binding and `}`
 with the final binding when this fits the line limit.
+Penalty: capital offence. This is one of the core associative-brace rules.
 
 #### Type literals
 
@@ -434,6 +628,8 @@ type Props = {
 
 Rule: type-literal `}` is not a block close. It must stay on the same line as
 the final property unless that would break the hard line limit.
+Penalty: capital offence. Mistaking a type-literal `}` for a block `}` is one
+of the recurring death-class errors.
 
 #### Object literals
 
@@ -474,6 +670,8 @@ const value = useMemo (() => ({
 Rule: object-literal `}` is associative-array-style syntax. It must not be on a
 line by itself. Keep it with the final property, and keep call `)` off the
 beginning of a line.
+Penalty: capital offence. Wrong object-literal `}` placement and wrong call
+`)` placement are both death-class violations here.
 
 #### Destructuring parameters
 
@@ -504,6 +702,8 @@ that spans multiple lines, do not use the Prettier-style `= ({ ... }) =>`
 shape. Put the function parameter list on its own lines. The destructuring `}`
 stays with the final binding. The parameter-list `)` is then allowed and
 required at the beginning of its own line.
+Penalty: capital offence. This pattern is a primary source of repeated TSX
+style regressions.
 
 #### Inline typed destructuring parameter
 
@@ -531,6 +731,8 @@ const RouteTransitionWrapper = ({ user, setUser }: {
 Rule: this is not a separately split parameter-list block. The line break is
 inside the inline type. Keep the type-literal `}` and parameter-list `)` on the
 same line as the final type property.
+Penalty: capital offence. Misclassifying this case means the delimiter review
+has failed at the syntax-role level.
 
 #### Multi-line normal parameter list
 
@@ -558,6 +760,8 @@ const updateDraft = <Key extends keyof Settings,> (
 Rule: when the parameter list itself is split across multiple parameter lines,
 the closing parameter `)` goes at the beginning of its own line before `=>` or
 the return type.
+Penalty: capital offence. This is the main allowed exception for a leading `)`,
+so getting it wrong destroys the whole rule set.
 
 #### Function and callback blocks
 
@@ -586,6 +790,8 @@ const handleSave = () => {
 Rule: block `}` closes executable code, not associative data. Multi-line
 function, lambda, callback, `if`, `for`, `switch`, and similar block braces
 belong on their own line.
+Penalty: capital offence. Confusing block `}` with associative `}` is a
+death-class delimiter error.
 
 #### Function and method calls
 
@@ -609,6 +815,8 @@ const value = compute (
 Rule: call-expression `)` must not be at the beginning of a line. The exception
 for leading `)` applies only to function declaration parameter lists, never to
 calls.
+Penalty: capital offence. A leading call `)` is one of the clearest death-class
+violations in this codebase.
 
 #### JSX closing markers
 
@@ -653,6 +861,8 @@ Good:
 
 Rule: keep `>` or `/>` with the final prop, and keep JSX closing parentheses in
 the local compact form such as `</div>)`.
+Penalty: medium-severity offence. It is usually not semantically broken, but it
+is a conspicuous TSX-style failure.
 
 #### Arrays and tuples
 
@@ -681,6 +891,8 @@ const items = [first, second]
 
 Rule: array and tuple `]` must not be at the beginning of a line. Keep it with
 the final element unless that would break the hard line limit.
+Penalty: capital offence. A leading `]` is forbidden by the same class of hard
+delimiter rule as leading associative `}` and leading call `)`.
 
 #### Single-line braces
 
@@ -705,6 +917,8 @@ Good:
 
 Rule: JavaScript object braces on one line get one inner space. JSX expression
 braces do not get inner spaces.
+Penalty: minor offence. This is not normally semantic breakage, but it still
+counts as a style miss.
 
 #### Final TypeScript/TSX self-review checklist
 

backend/db/schema.rb

@@ -72,6 +72,7 @@ ActiveRecord::Schema[8.0].define(version: 2026_07_05_000000) do
     t.index ["correct_post_id"], name: "index_gekanator_games_on_correct_post_id"
     t.index ["guessed_post_id"], name: "index_gekanator_games_on_guessed_post_id"
     t.index ["user_id"], name: "index_gekanator_games_on_user_id"
+    t.check_constraint "`question_count` >= 0", name: "chk_gekanator_games_question_count_nonnegative"
   end
 
   create_table "gekanator_question_examples", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
@@ -274,9 +275,10 @@ ActiveRecord::Schema[8.0].define(version: 2026_07_05_000000) do
     t.datetime "created_at", null: false
     t.bigint "created_by_user_id"
     t.index ["created_at"], name: "index_nico_tag_versions_on_created_at"
-    t.index ["created_by_user_id", "created_at"], name: "index_nico_tag_versions_on_created_by_user_id_and_created_at"
-    t.index ["tag_id", "created_at"], name: "index_nico_tag_versions_on_tag_id_and_created_at"
+    t.index ["created_by_user_id", "created_at"], name: "index_nico_tag_versions_on_created_by_user_id_and_created_at", order: { created_at: :desc }
+    t.index ["tag_id", "created_at"], name: "index_nico_tag_versions_on_tag_id_and_created_at", order: { created_at: :desc }
     t.index ["tag_id", "version_no"], name: "index_nico_tag_versions_on_tag_id_and_version_no", unique: true
+    t.check_constraint "`version_no` > 0", name: "nico_tag_versions_version_no_positive"
   end
 
   create_table "post_implications", primary_key: ["post_id", "parent_post_id"], charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
@@ -285,13 +287,14 @@ ActiveRecord::Schema[8.0].define(version: 2026_07_05_000000) do
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
     t.index ["parent_post_id"], name: "index_post_implications_on_parent_post_id"
+    t.check_constraint "`post_id` <> `parent_post_id`", name: "chk_post_implications_no_self"
   end
 
   create_table "post_similarities", primary_key: ["post_id", "target_post_id"], charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.bigint "post_id", null: false
     t.bigint "target_post_id", null: false
     t.float "cos", null: false
-    t.index ["post_id", "cos"], name: "index_post_similarities_on_post_id_and_cos"
+    t.index ["post_id", "cos"], name: "index_post_similarities_on_post_id_and_cos", order: { cos: :desc }
     t.index ["target_post_id"], name: "index_post_similarities_on_target_post_id"
   end
 
@@ -347,6 +350,8 @@ ActiveRecord::Schema[8.0].define(version: 2026_07_05_000000) do
     t.index ["post_id"], name: "index_post_versions_on_post_id"
     t.index ["video_ms", "post_id"], name: "idx_post_versions_video_ms_post_id"
     t.check_constraint "(`video_ms` is null) or (`video_ms` > 0)", name: "chk_post_versions_video_ms_positive"
+    t.check_constraint "`event_type` in (_utf8mb4'create',_utf8mb4'update',_utf8mb4'discard',_utf8mb4'restore')", name: "post_versions_event_type_valid"
+    t.check_constraint "`version_no` > 0", name: "post_versions_version_no_positive"
   end
 
   create_table "posts", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
@@ -364,6 +369,7 @@ ActiveRecord::Schema[8.0].define(version: 2026_07_05_000000) do
     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
 
   create_table "settings", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
@@ -371,18 +377,25 @@ ActiveRecord::Schema[8.0].define(version: 2026_07_05_000000) do
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
     t.string "theme", default: "system", null: false
-    t.string "display_density", default: "comfortable", null: false
-    t.string "font_size", default: "normal", null: false
-    t.integer "post_list_limit", default: 50, null: false
-    t.string "post_list_order", default: "created_at_desc", null: false
-    t.string "viewed_post_display", default: "show", null: false
-    t.boolean "tag_autocomplete_nico", default: true, null: false
     t.string "auto_fetch_title", default: "manual", null: false
     t.string "auto_fetch_thumbnail", default: "manual", null: false
     t.string "wiki_editor_mode", default: "split", null: false
     t.index ["user_id"], name: "index_settings_on_user_id", unique: true
   end
 
+  create_table "wiki_assets", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
+    t.bigint "wiki_page_id", null: false
+    t.integer "no", null: false
+    t.string "alt_text"
+    t.binary "sha256", limit: 32, null: false
+    t.bigint "created_by_user_id", null: false
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["created_by_user_id"], name: "index_wiki_assets_on_created_by_user_id"
+    t.index ["wiki_page_id", "no"], name: "index_wiki_assets_on_wiki_page_id_and_no", unique: true
+    t.index ["wiki_page_id", "sha256"], name: "index_wiki_assets_on_wiki_page_id_and_sha256", unique: true
+  end
+
   create_table "tag_implications", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.bigint "tag_id", null: false
     t.bigint "parent_tag_id", null: false
@@ -418,7 +431,7 @@ ActiveRecord::Schema[8.0].define(version: 2026_07_05_000000) do
     t.bigint "tag_id", null: false
     t.bigint "target_tag_id", null: false
     t.float "cos", null: false
-    t.index ["tag_id", "cos"], name: "index_tag_similarities_on_tag_id_and_cos"
+    t.index ["tag_id", "cos"], name: "index_tag_similarities_on_tag_id_and_cos", order: { cos: :desc }
     t.index ["target_tag_id"], name: "index_tag_similarities_on_target_tag_id"
   end
 
@@ -434,9 +447,10 @@ ActiveRecord::Schema[8.0].define(version: 2026_07_05_000000) do
     t.datetime "created_at", null: false
     t.bigint "created_by_user_id"
     t.index ["created_at"], name: "index_tag_versions_on_created_at"
-    t.index ["created_by_user_id", "created_at"], name: "index_tag_versions_on_created_by_user_id_and_created_at"
-    t.index ["tag_id", "created_at"], name: "index_tag_versions_on_tag_id_and_created_at"
+    t.index ["created_by_user_id", "created_at"], name: "index_tag_versions_on_created_by_user_id_and_created_at", order: { created_at: :desc }
+    t.index ["tag_id", "created_at"], name: "index_tag_versions_on_tag_id_and_created_at", order: { created_at: :desc }
     t.index ["tag_id", "version_no"], name: "index_tag_versions_on_tag_id_and_version_no", unique: true
+    t.check_constraint "`version_no` > 0", name: "tag_versions_version_no_positive"
   end
 
   create_table "tags", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
@@ -452,6 +466,7 @@ ActiveRecord::Schema[8.0].define(version: 2026_07_05_000000) do
     t.index ["discarded_at"], name: "index_tags_on_discarded_at"
     t.index ["tag_name_id"], name: "index_tags_on_tag_name_id", unique: true
     t.check_constraint "(`deprecated_at` is null) or (`category` <> _utf8mb4'nico')", name: "chk_tags_deprecated_at_not_nico"
+    t.check_constraint "`version_no` > 0", name: "chk_tags_version_no_positive"
   end
 
   create_table "theatre_comments", primary_key: ["theatre_id", "no"], charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
@@ -605,11 +620,13 @@ ActiveRecord::Schema[8.0].define(version: 2026_07_05_000000) do
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
     t.datetime "discarded_at"
+    t.integer "next_asset_no", default: 1, null: false
     t.integer "version_no", null: false
     t.index ["created_user_id"], name: "index_wiki_pages_on_created_user_id"
     t.index ["discarded_at"], name: "index_wiki_pages_on_discarded_at"
     t.index ["tag_name_id"], name: "index_wiki_pages_on_tag_name_id", unique: true
     t.index ["updated_user_id"], name: "index_wiki_pages_on_updated_user_id"
+    t.check_constraint "`version_no` > 0", name: "chk_wiki_pages_version_no_positive"
   end
 
   create_table "wiki_revision_lines", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
@@ -654,6 +671,8 @@ ActiveRecord::Schema[8.0].define(version: 2026_07_05_000000) do
     t.index ["created_by_user_id"], name: "index_wiki_versions_on_created_by_user_id"
     t.index ["wiki_page_id", "version_no"], name: "index_wiki_versions_on_wiki_page_id_and_version_no", unique: true
     t.index ["wiki_page_id"], name: "index_wiki_versions_on_wiki_page_id"
+    t.check_constraint "`event_type` in (_utf8mb4'create',_utf8mb4'update',_utf8mb4'discard',_utf8mb4'restore')", name: "wiki_versions_event_type_valid"
+    t.check_constraint "`version_no` > 0", name: "wiki_versions_version_no_positive"
   end
 
   add_foreign_key "active_storage_attachments", "active_storage_blobs", column: "blob_id"
@@ -735,6 +754,8 @@ ActiveRecord::Schema[8.0].define(version: 2026_07_05_000000) do
   add_foreign_key "user_post_views", "posts"
   add_foreign_key "user_post_views", "users"
   add_foreign_key "user_theme_slots", "users"
+  add_foreign_key "wiki_assets", "users", column: "created_by_user_id"
+  add_foreign_key "wiki_assets", "wiki_pages"
   add_foreign_key "wiki_pages", "tag_names"
   add_foreign_key "wiki_pages", "users", column: "created_user_id"
   add_foreign_key "wiki_pages", "users", column: "updated_user_id"

backend/spec/models/setting_spec.rb

@@ -0,0 +1,34 @@
+require 'rails_helper'
+
+RSpec.describe Setting, type: :model do
+  it 'accepts the default typed user settings' do
+    setting = described_class.new({ user: create(:user) }.merge(described_class.defaults))
+
+    expect(setting).to be_valid
+  end
+
+  it 'requires one settings row per user' do
+    user = create(:user)
+    described_class.create!({ user: }.merge(described_class.defaults))
+
+    duplicate = described_class.new({ user: }.merge(described_class.defaults))
+
+    expect(duplicate).not_to be_valid
+    expect(duplicate.errors[:user_id]).to be_present
+  end
+
+  it 'validates enum-like settings columns' do
+    setting = described_class.new(
+        { user: create(:user),
+          theme: 'neon',
+          auto_fetch_title: 'sometimes',
+          auto_fetch_thumbnail: 'sometimes',
+          wiki_editor_mode: 'sideways' })
+
+    expect(setting).not_to be_valid
+    expect(setting.errors[:theme]).to be_present
+    expect(setting.errors[:auto_fetch_title]).to be_present
+    expect(setting.errors[:auto_fetch_thumbnail]).to be_present
+    expect(setting.errors[:wiki_editor_mode]).to be_present
+  end
+end

backend/spec/models/user_theme_slot_spec.rb

@@ -0,0 +1,40 @@
+require 'rails_helper'
+
+RSpec.describe UserThemeSlot, type: :model do
+  it 'accepts a theme slot for one user, base theme, and slot number' do
+    slot = described_class.new(user: create(:user),
+                               base_theme: 'light',
+                               slot_no: 1,
+                               tokens: { 'background' => '0 0% 100%' })
+
+    expect(slot).to be_valid
+  end
+
+  it 'requires unique slot numbers per user and base theme' do
+    user = create(:user)
+    described_class.create!(user:,
+                            base_theme: 'dark',
+                            slot_no: 2,
+                            tokens: { 'background' => '222.2 84% 4.9%' })
+
+    duplicate = described_class.new(user:,
+                                    base_theme: 'dark',
+                                    slot_no: 2,
+                                    tokens: { 'background' => '0 0% 100%' })
+
+    expect(duplicate).not_to be_valid
+    expect(duplicate.errors[:user_id]).to be_present
+  end
+
+  it 'validates base theme, slot number, and token object shape' do
+    slot = described_class.new(user: create(:user),
+                               base_theme: 'system',
+                               slot_no: 4,
+                               tokens: 'not-object')
+
+    expect(slot).not_to be_valid
+    expect(slot.errors[:base_theme]).to be_present
+    expect(slot.errors[:slot_no]).to be_present
+    expect(slot.errors[:tokens]).to be_present
+  end
+end

backend/spec/requests/user_settings_spec.rb

@@ -0,0 +1,98 @@
+require 'rails_helper'
+
+RSpec.describe 'user settings', type: :request do
+  describe 'GET /users/settings' do
+    it 'requires a current user' do
+      sign_out
+
+      get '/users/settings'
+
+      expect(response).to have_http_status(:unauthorized)
+    end
+
+    it 'returns defaults and creates a missing settings row' do
+      user = create(:user)
+      sign_in_as(user)
+
+      expect {
+        get '/users/settings'
+      }.to change(Setting, :count).by(1)
+
+      expect(response).to have_http_status(:ok)
+      expect(json).to eq(
+          'theme' => 'system',
+          'auto_fetch_title' => 'manual',
+          'auto_fetch_thumbnail' => 'manual',
+          'wiki_editor_mode' => 'split')
+      expect(user.reload.setting).to be_present
+    end
+  end
+
+  describe 'PATCH /users/settings' do
+    it 'requires a current user' do
+      sign_out
+
+      patch '/users/settings', params: { theme: 'dark' }, as: :json
+
+      expect(response).to have_http_status(:unauthorized)
+    end
+
+    it 'updates multiple typed settings at once' do
+      user = create(:user)
+      sign_in_as(user)
+
+      patch '/users/settings',
+            params: {
+              theme: 'dark',
+              auto_fetch_title: 'auto',
+              auto_fetch_thumbnail: 'off',
+              wiki_editor_mode: 'preview' },
+            as: :json
+
+      expect(response).to have_http_status(:ok)
+      expect(json).to include(
+          'theme' => 'dark',
+          'auto_fetch_title' => 'auto',
+          'auto_fetch_thumbnail' => 'off',
+          'wiki_editor_mode' => 'preview')
+      expect(user.reload.setting).to have_attributes(
+          theme: 'dark',
+          auto_fetch_title: 'auto',
+          auto_fetch_thumbnail: 'off',
+          wiki_editor_mode: 'preview')
+    end
+
+    it 'does not treat Rails parameter wrapping as an editable setting' do
+      user = create(:user)
+      sign_in_as(user)
+
+      patch '/users/settings',
+            params: { theme: 'light', user_setting: { theme: 'dark' } },
+            as: :json
+
+      expect(response).to have_http_status(:ok)
+      expect(user.reload.setting.theme).to eq('light')
+    end
+
+    it 'returns validation_error for type mismatches' do
+      sign_in_as(create(:user))
+
+      patch '/users/settings', params: { theme: 1 }, as: :json
+
+      expect(response).to have_http_status(:unprocessable_entity)
+      expect(json).to include('type' => 'validation_error')
+      expect(json.fetch('errors')).to include(
+          'theme' => ['値の型が不正です．'])
+    end
+
+    it 'returns validation_error for invalid enum values' do
+      sign_in_as(create(:user))
+
+      patch '/users/settings', params: { theme: 'neon' }, as: :json
+
+      expect(response).to have_http_status(:unprocessable_entity)
+      expect(json).to include('type' => 'validation_error')
+      expect(json.fetch('errors').fetch('theme')).to be_present
+    end
+  end
+end

backend/spec/requests/user_theme_slots_spec.rb

@@ -0,0 +1,104 @@
+require 'rails_helper'
+
+RSpec.describe 'user theme slots', type: :request do
+  describe 'GET /users/theme_slots' do
+    it 'requires a current user' do
+      sign_out
+
+      get '/users/theme_slots'
+
+      expect(response).to have_http_status(:unauthorized)
+    end
+
+    it 'returns only the current user slots in stable order' do
+      user = create(:user)
+      other_user = create(:user)
+      sign_in_as(user)
+      UserThemeSlot.create!(user:, base_theme: 'light', slot_no: 2, tokens: { 'a' => 1 })
+      UserThemeSlot.create!(user:, base_theme: 'dark', slot_no: 1, tokens: { 'b' => 2 })
+      UserThemeSlot.create!(user: other_user,
+                            base_theme: 'dark',
+                            slot_no: 3,
+                            tokens: { 'c' => 3 })
+
+      get '/users/theme_slots'
+
+      expect(response).to have_http_status(:ok)
+      expect(json.map { |slot| [slot.fetch('base_theme'), slot.fetch('slot_no')] }).to eq(
+          [['dark', 1], ['light', 2]])
+      expect(json.map { |slot| slot.fetch('tokens') }).to eq(
+          [{ 'b' => 2 }, { 'a' => 1 }])
+    end
+  end
+
+  describe 'PUT /users/theme_slots/:base_theme/:slot_no' do
+    it 'requires a current user' do
+      sign_out
+
+      put '/users/theme_slots/light/1',
+          params: { tokens: { background: '0 0% 100%' } },
+          as: :json
+
+      expect(response).to have_http_status(:unauthorized)
+    end
+
+    it 'creates a theme slot' do
+      user = create(:user)
+      sign_in_as(user)
+
+      expect {
+        put '/users/theme_slots/light/1',
+            params: { tokens: { background: '0 0% 100%', tagColours: { nico: '#ffffff' } } },
+            as: :json
+      }.to change(UserThemeSlot, :count).by(1)
+
+      expect(response).to have_http_status(:ok)
+      expect(json).to include('base_theme' => 'light', 'slot_no' => 1)
+      expect(json.fetch('tokens')).to include(
+          'background' => '0 0% 100%',
+          'tagColours' => { 'nico' => '#ffffff' })
+      expect(user.theme_slots.find_by!(base_theme: 'light', slot_no: 1).tokens).to include(
+          'background' => '0 0% 100%')
+    end
+
+    it 'updates an existing theme slot instead of creating a duplicate' do
+      user = create(:user)
+      sign_in_as(user)
+      UserThemeSlot.create!(user:, base_theme: 'dark', slot_no: 2, tokens: { 'old' => true })
+
+      expect {
+        put '/users/theme_slots/dark/2',
+            params: { tokens: { background: '222.2 84% 4.9%' } },
+            as: :json
+      }.not_to change(UserThemeSlot, :count)
+
+      expect(response).to have_http_status(:ok)
+      expect(user.theme_slots.find_by!(base_theme: 'dark', slot_no: 2).tokens).to eq(
+          'background' => '222.2 84% 4.9%')
+    end
+
+    it 'rejects invalid path parameters and token shapes' do
+      sign_in_as(create(:user))
+
+      put '/users/theme_slots/system/4',
+          params: { tokens: 'not-object' },
+          as: :json
+
+      expect(response).to have_http_status(:unprocessable_entity)
+      expect(json.fetch('errors')).to include(
+          'base_theme' => ['値が不正です．'])
+    end
+
+    it 'rejects non-object tokens for valid slots' do
+      sign_in_as(create(:user))
+
+      put '/users/theme_slots/light/1',
+          params: { tokens: 'not-object' },
+          as: :json
+
+      expect(response).to have_http_status(:unprocessable_entity)
+      expect(json.fetch('errors')).to include(
+          'tokens' => ['JSON object で指定してください．'])
+    end
+  end
+end

frontend/src/App.tsx

@@ -1,5 +1,5 @@
 import { AnimatePresence, LayoutGroup, MotionConfig, motion } from 'framer-motion'
-import { useEffect, useMemo, useState } from 'react'
+import { Fragment, useEffect, useMemo, useState } from 'react'
 import { BrowserRouter,
 	 Navigate,
 	 Route,
@@ -12,7 +12,9 @@ import TopNav from '@/components/TopNav'
 import DialogueProvider from '@/components/dialogues/DialogueProvider'
 import { Toaster } from '@/components/ui/toaster'
 import { apiPost, isApiError } from '@/lib/api'
-import { applyClientAppearance,
+import { applyClientAnimationMode,
+	 applyClientAppearance,
+	 type ClientAnimationMode,
 	 fetchUserThemeSlots,
 	 fetchUserSettings,
 	 getClientThemeMode,
@@ -21,6 +23,7 @@ import { applyClientAppearance,
 	 setCachedUserThemeSlots,
 	 seedClientThemeMode } from '@/lib/settings'
 import { useClientBehaviourSettings } from '@/lib/useClientBehaviourSettings'
+import { UnsavedChangesGuardProvider } from '@/lib/useUnsavedChangesGuard'
 
 import { KeyboardShortcutsProvider } from '@/lib/useKeyboardShortcuts'
 import DeerjikistDetailPage from '@/pages/deerjikists/DeerjikistDetailPage'
@@ -59,11 +62,51 @@ import type { Dispatch, FC, SetStateAction } from 'react'
 import type { User } from '@/types'
 
 
-const RouteTransitionWrapper = ({ user, setUser }: {
+const RouteTransitionWrapper = ({ animationMode, user, setUser }: {
+    animationMode: ClientAnimationMode
     user:     User | null
     setUser:  Dispatch<SetStateAction<User | null>> }) => {
   const location = useLocation ()
 
+  if (animationMode === 'off')
+    {
+      return (
+	  <Routes location={location}>
+	    <Route path="/" element={<Navigate to="/posts" replace/>}/>
+	    <Route path="/posts" element={<PostListPage/>}/>
+	    <Route path="/posts/new" element={<PostNewPage user={user}/>}/>
+	    <Route path="/posts/search" element={<PostSearchPage/>}/>
+	    <Route path="/posts/:id" element={<PostDetailRoute user={user}/>}/>
+	    <Route path="/posts/changes" element={<PostHistoryPage/>}/>
+	    <Route path="/tags" element={<TagListPage/>}/>
+	    <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 user={user}/>}/>
+	    <Route path="/materials" element={<MaterialBasePage/>}>
+	      <Route index element={<MaterialListPage/>}/>
+	      <Route path="changes" element={<MaterialHistoryPage/>}/>
+	      <Route path="new" element={<MaterialNewPage/>}/>
+	      <Route path="suppressions" element={<MaterialSyncSuppressionsPage/>}/>
+	      <Route path=":id" element ={<MaterialDetailPage/>}/>
+	    </Route>
+	    <Route path="/wiki" element={<WikiSearchPage/>}/>
+	    <Route path="/wiki/:title" element={<WikiDetailPage/>}/>
+	    <Route path="/wiki/new" element={<WikiNewPage user={user}/>}/>
+	    <Route path="/wiki/:id/edit" element={<WikiEditPage user={user}/>}/>
+	    <Route path="/wiki/:id/diff" element={<WikiDiffPage/>}/>
+	    <Route path="/wiki/changes" element={<WikiHistoryPage/>}/>
+	    <Route path="/users/settings" element={<SettingPage user={user} setUser={setUser}/>}/>
+	    <Route path="/settings" element={<Navigate to="/users/settings" replace/>}/>
+	    <Route path="/tos" element={<TOSPage/>}/>
+	    <Route path="/gekanator" element={<GekanatorPage user={user}/>}/>
+	    <Route path="/more" element={<MorePage/>}/>
+	    <Route path="*" element={<NotFound/>}/>
+	  </Routes>)
+    }
+
   return (
       <AnimatePresence mode="wait">
 	<Routes location={location}>
@@ -116,6 +159,7 @@ const App: FC = () => {
   const [status, setStatus] = useState (200)
   const behaviourSettings = useClientBehaviourSettings ()
   const animationMode = behaviourSettings.animation ?? 'normal'
+  const LayoutWrapper = animationMode === 'off' ? Fragment : LayoutGroup
 
   const appLayoutTransition = useMemo (
       () => (
@@ -141,6 +185,10 @@ const App: FC = () => {
     return () => mediaQuery.removeEventListener ('change', handleThemeChange)
   }, [])
 
+  useEffect (() => {
+    applyClientAnimationMode (animationMode)
+  }, [animationMode])
+
   useEffect (() => {
     const createUser = async () => {
       const data = await apiPost<{ code: string; user: User }> ('/users')
@@ -210,8 +258,9 @@ const App: FC = () => {
 	{import.meta.env.DEV && <DevModeWatermark/>}
 
 	<BrowserRouter>
-	  <KeyboardShortcutsProvider>
-	    <DialogueProvider>
+	  <DialogueProvider>
+	    <UnsavedChangesGuardProvider>
+	      <KeyboardShortcutsProvider>
 	      <MotionConfig
 		  reducedMotion={
 		      animationMode === 'normal'
@@ -220,20 +269,24 @@ const App: FC = () => {
 			? 'user'
 			: 'always'
 		  }>
-		<LayoutGroup>
+		<LayoutWrapper>
 		  <motion.div
 		      layout={animationMode === 'off' ? false : 'position'}
 		      transition={{ layout: appLayoutTransition }}
 		      className="relative flex flex-col h-dvh w-full overflow-y-hidden">
 		    <TopNav user={user}/>
-		    <RouteTransitionWrapper user={user} setUser={setUser}/>
+		    <RouteTransitionWrapper
+			animationMode={animationMode}
+			user={user}
+			setUser={setUser}/>
 		  </motion.div>
-		</LayoutGroup>
+		</LayoutWrapper>
 	      </MotionConfig>
 
 	      <Toaster/>
-	    </DialogueProvider>
-	  </KeyboardShortcutsProvider>
+	      </KeyboardShortcutsProvider>
+	    </UnsavedChangesGuardProvider>
+	  </DialogueProvider>
 	</BrowserRouter>
       </>)
 }

frontend/src/components/DraggableDroppableTagRow.test.tsx

@@ -0,0 +1,75 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+
+import DraggableDroppableTagRow from '@/components/DraggableDroppableTagRow'
+import { buildTag } from '@/test/factories'
+import { renderWithProviders } from '@/test/render'
+
+const dndKit = vi.hoisted (() => ({
+  useDraggable: vi.fn (),
+  useDroppable: vi.fn (),
+}))
+
+vi.mock ('@dnd-kit/core', () => dndKit)
+
+const tag = buildTag ({ id: 7, name: 'ドラッグ元', postCount: 3 })
+
+const renderRow = (activeDndId?: string) => {
+  renderWithProviders (
+      <DraggableDroppableTagRow
+          activeDndId={activeDndId}
+          tag={tag}
+          nestLevel={2}
+          pathKey="cat-general-7"
+          suppressClickRef={{ current: false }}/>,
+  )
+}
+
+const tagBody = (): HTMLElement => {
+  const link = document.querySelector<HTMLElement> ('a[title="ドラッグ元"]')
+
+  if (link == null)
+    throw new Error ('tag link not found')
+
+  const body = link.closest ('div')
+
+  if (body == null)
+    throw new Error ('tag body not found')
+
+  return body
+}
+
+describe ('DraggableDroppableTagRow', () => {
+  beforeEach (() => {
+    vi.clearAllMocks ()
+    dndKit.useDraggable.mockReturnValue ({
+        attributes: { 'aria-describedby': 'drag-source' },
+        listeners:  { onPointerDown: vi.fn () },
+        setNodeRef: vi.fn (),
+        transform:  null })
+    dndKit.useDroppable.mockReturnValue ({
+        isOver:     false,
+        setNodeRef: vi.fn () })
+  })
+
+  it ('passes dndId through draggable data for active-row tracking', () => {
+    renderRow ()
+
+    expect (dndKit.useDraggable).toHaveBeenCalledWith (
+        expect.objectContaining ({
+            id:   'tag-node:cat-general-7',
+            data: expect.objectContaining ({
+                dndId:     'tag-node:cat-general-7',
+                nestLevel: 2,
+                tagId:     7 }) }))
+  })
+
+  it ('hides only the active drag source from the explicit active dnd id', () => {
+    renderRow ('tag-node:cat-general-7')
+    expect (tagBody ()).toHaveStyle ({ visibility: 'hidden' })
+  })
+
+  it ('keeps inactive tag rows visible while another tag is dragged', () => {
+    renderRow ('tag-node:other')
+    expect (tagBody ()).toHaveStyle ({ visibility: 'visible' })
+  })
+})

frontend/src/components/DraggableDroppableTagRow.tsx

@@ -4,6 +4,8 @@ import { motion } from 'framer-motion'
 import { useRef } from 'react'
 
 import TagLink from '@/components/TagLink'
+import { clientAnimationTransition } from '@/lib/clientAnimation'
+import { useClientBehaviourSettings } from '@/lib/useClientBehaviourSettings'
 import { cn } from '@/lib/utils'
 
 import type { CSSProperties, FC, MutableRefObject } from 'react'
@@ -11,6 +13,7 @@ import type { CSSProperties, FC, MutableRefObject } from 'react'
 import type { Tag } from '@/types'
 
 type Props = {
+    activeDndId?:      string
     tag:              Tag
     nestLevel:        number
     pathKey:          string
@@ -19,7 +22,21 @@ type Props = {
     sp?:              boolean }
 
 
-const DraggableDroppableTagRow: FC<Props> = ({ tag, nestLevel, pathKey, parentTagId, suppressClickRef, sp }) => {
+const DraggableDroppableTagRow: FC<Props> = ({
+    activeDndId,
+    tag,
+    nestLevel,
+    pathKey,
+    parentTagId,
+    suppressClickRef,
+    sp,
+}) => {
+  const behaviourSettings = useClientBehaviourSettings ()
+  const animationMode = behaviourSettings.animation ?? 'normal'
+  const layoutTransition = clientAnimationTransition (
+      animationMode,
+      { normal: { duration: .2, ease: 'easeOut' as const } },
+  )
   const dndId = `tag-node:${ pathKey }`
 
   const downPosRef = useRef<{ x: number; y: number } | null> (null)
@@ -45,18 +62,23 @@ const DraggableDroppableTagRow: FC<Props> = ({ tag, nestLevel, pathKey, parentTa
   const { attributes,
 	  listeners,
 	  setNodeRef: setDragRef,
-	  transform,
-	  isDragging: dragging } = useDraggable ({ id:    dndId,
-						   data:  { kind:   'tag',
-							    tagId:  tag.id,
-							    parentTagId } })
+	  transform } = useDraggable ({ id:    dndId,
+					data:  { kind:   'tag',
+						 dndId,
+						 tagId:  tag.id,
+						 parentTagId,
+						 nestLevel } })
 
   const { setNodeRef: setDropRef, isOver: over } = useDroppable ({
       id:   dndId,
       data: { kind: 'tag', tagId: tag.id } })
 
+  const activeDragging = activeDndId === dndId
   const style: CSSProperties = { transform:   CSS.Translate.toString (transform),
-				 visibility:  dragging ? 'hidden' : 'visible' }
+				 visibility:  activeDragging ? 'hidden' : 'visible' }
+  const innerClassName = cn (
+      'inline-flex min-w-0 max-w-full items-baseline overflow-hidden',
+      sp && 'touch-pan-y')
 
   return (
       <div
@@ -69,12 +91,16 @@ const DraggableDroppableTagRow: FC<Props> = ({ tag, nestLevel, pathKey, parentTa
 	      return
 	    const dx = e.clientX - p.x
 	    const dy = e.clientY - p.y
+
 	    if (dx * dx + dy * dy >= 9)
 	      armEatNextClick ()
 	  }}
 	  onPointerUpCapture={() => {
 	    downPosRef.current = null
 	  }}
+	  onPointerCancelCapture={() => {
+	    downPosRef.current = null
+	  }}
 	  onClickCapture={e => {
 	    if (suppressClickRef.current)
 	      {
@@ -82,22 +108,35 @@ const DraggableDroppableTagRow: FC<Props> = ({ tag, nestLevel, pathKey, parentTa
 		e.stopPropagation ()
 	      }
 	  }}
-	  ref={node => {
-	    setDragRef (node)
-	    setDropRef (node)
-	  }}
-	  style={style}
+	  ref={setDropRef}
 	  className={cn (
 	      'min-w-0 max-w-full overflow-hidden rounded select-none',
+	      sp && 'touch-pan-y',
 	      over && 'ring-2 ring-offset-2')}
-	  {...attributes}
-	  {...listeners}>
-	<motion.div
-	    className="flex min-w-0 max-w-full items-baseline overflow-hidden"
-	    transition={{ layout: { duration: .2, ease: 'easeOut' } }}
-	    layoutId={`tag-${ sp ? 'sp-' : '' }${ tag.id }`}>
-	  <TagLink tag={tag} nestLevel={nestLevel}/>
-	</motion.div>
+	  >
+	{activeDragging
+	 ? (
+	    <div
+		ref={setDragRef}
+		style={style}
+		className={innerClassName}
+		{...attributes}
+		{...listeners}>
+	      <TagLink tag={tag} nestLevel={nestLevel}/>
+	    </div>)
+	 : (
+	    <motion.div
+		ref={setDragRef}
+		style={style}
+		className={innerClassName}
+		{...attributes}
+		{...listeners}
+		transition={{ layout: layoutTransition }}
+		layoutId={animationMode === 'off'
+		    ? undefined
+		    : `tag-${ sp ? 'sp-' : '' }${ tag.id }`}>
+	      <TagLink tag={tag} nestLevel={nestLevel}/>
+	    </motion.div>)}
       </div>)
 }
 

frontend/src/components/PrefetchLink.tsx

@@ -6,6 +6,7 @@ import { createPath, useNavigate } from 'react-router-dom'
 import { useOverlayStore } from '@/components/RouteBlockerOverlay'
 import { prefetchForURL } from '@/lib/prefetchers'
 import { useClientBehaviourSettings } from '@/lib/useClientBehaviourSettings'
+import { useUnsavedChangesGuard } from '@/lib/useUnsavedChangesGuard'
 import { cn } from '@/lib/utils'
 
 import type { AnchorHTMLAttributes, MouseEvent, TouchEvent } from 'react'
@@ -35,11 +36,19 @@ export default forwardRef<HTMLAnchorElement, Props> (({
   const navigate = useNavigate ()
   const qc = useQueryClient ()
   const behaviourSettings = useClientBehaviourSettings ()
+  const { confirmDiscardNavigation } = useUnsavedChangesGuard ()
   const linkPreloadMode = behaviourSettings.linkPreload ?? 'intent'
+  const path = useMemo (
+      () => typeof to === 'string' ? to : createPath (to),
+      [to],
+  )
   const url = useMemo (() => {
-    const path = (typeof to === 'string') ? to : createPath (to)
-    return (new URL (path, location.origin)).toString ()
-  }, [to])
+    return (new URL (path, window.location.origin)).toString ()
+  }, [path])
+  const nextPathname = useMemo (
+      () => (new URL (path, window.location.origin)).pathname,
+      [path],
+  )
   const setOverlay = useOverlayStore (s => s.setActive)
 
   const doPrefetch = async () => {
@@ -84,6 +93,13 @@ export default forwardRef<HTMLAnchorElement, Props> (({
 
       ev.preventDefault ()
 
+      if (nextPathname !== window.location.pathname)
+	{
+	  const confirmed = await confirmDiscardNavigation ()
+	  if (!(confirmed))
+	    return
+	}
+
       flushSync (() => {
 	setOverlay (true)
       })
@@ -106,7 +122,7 @@ export default forwardRef<HTMLAnchorElement, Props> (({
 
   return (
       <a ref={ref}
-	 href={typeof to === 'string' ? to : createPath (to)}
+	 href={path}
 	 onMouseEnter={handleMouseEnter}
 	 onTouchStart={handleTouchStart}
 	 onClick={handleClick}

frontend/src/components/ResponsiveMarqueeText.tsx

@@ -1,3 +1,4 @@
+import { useClientBehaviourSettings } from '@/lib/useClientBehaviourSettings'
 import { cn } from '@/lib/utils'
 import { useEffect, useRef, useState } from 'react'
 
@@ -20,6 +21,8 @@ const MIN_MARQUEE_OVERFLOW_PX = 1
 const ResponsiveMarqueeText: FC<Props> = (
     { text, className, truncateOnMobile = false, title },
 ) => {
+  const behaviourSettings = useClientBehaviourSettings ()
+  const animationMode = behaviourSettings.animation ?? 'normal'
   const outerRef = useRef<HTMLSpanElement | null> (null)
   const staticRef = useRef<HTMLSpanElement | null> (null)
   const animatedRef = useRef<HTMLSpanElement | null> (null)
@@ -98,6 +101,7 @@ const ResponsiveMarqueeText: FC<Props> = (
     const animated = animatedRef.current
     const canMarquee = (
         active
+        && animationMode !== 'off'
         && desktopMarqueeEnabled
         && overflowPx >= MIN_MARQUEE_OVERFLOW_PX
         && animated != null)
@@ -207,7 +211,7 @@ const ResponsiveMarqueeText: FC<Props> = (
       resetAnimated ()
       setMarqueeVisible (false)
     }
-  }, [active, desktopMarqueeEnabled, overflowPx, text])
+  }, [active, animationMode, desktopMarqueeEnabled, overflowPx, text])
 
   return (
       <span

frontend/src/components/TagDetailSidebar.tsx

@@ -1,11 +1,13 @@
 import { DndContext,
 	 DragOverlay,
+	 MeasuringStrategy,
 	 MouseSensor,
 	 TouchSensor,
+	 pointerWithin,
 	 useDroppable,
 	 useSensor,
 	 useSensors } from '@dnd-kit/core'
-import { restrictToWindowEdges } from '@dnd-kit/modifiers'
+import { restrictToWindowEdges, snapCenterToCursor } from '@dnd-kit/modifiers'
 import { useQueryClient } from '@tanstack/react-query'
 import { motion } from 'framer-motion'
 import { useEffect, useMemo, useRef, useState } from 'react'
@@ -20,22 +22,28 @@ import SidebarComponent from '@/components/layout/SidebarComponent'
 import { toast } from '@/components/ui/use-toast'
 import { CATEGORIES, CATEGORY_NAMES } from '@/consts'
 import { apiDelete, apiGet, apiPatch, apiPost } from '@/lib/api'
+import { clientAnimationTransition } from '@/lib/clientAnimation'
 import { postsKeys, tagsKeys } from '@/lib/queryKeys'
 import { useClientBehaviourSettings } from '@/lib/useClientBehaviourSettings'
 import { dateString, originalCreatedAtString } from '@/lib/utils'
 
-import type { DragEndEvent } from '@dnd-kit/core'
+import type { CollisionDetection, DragEndEvent } from '@dnd-kit/core'
 import type { FC, MutableRefObject, ReactNode } from 'react'
 
 import type { Category, Post, TagWithSections } from '@/types'
 
 type TagByCategory = { [key in Category]: TagWithSections[] }
-type FlatTagRow = {
-    tag:          TagWithSections
-    parentTagId?: number }
+
+const tagCollisionDetection: CollisionDetection = args => {
+  return pointerWithin (args)
+}
+
+const alwaysMeasureDroppables = {
+    droppable: { strategy: MeasuringStrategy.Always } } as const
 
 
 const renderTagTree = (
+    activeDndId:       string | undefined,
     tag:              TagWithSections,
     nestLevel:        number,
     path:             string,
@@ -47,6 +55,7 @@ const renderTagTree = (
   const self = (
       <li key={key} className="mb-1">
 	<DraggableDroppableTagRow
+	    activeDndId={activeDndId}
 	    tag={tag}
 	    nestLevel={nestLevel}
 	    pathKey={key}
@@ -60,38 +69,17 @@ const renderTagTree = (
       ...((tag.children
 	   ?.sort ((a, b) => a.name < b.name ? -1 : 1)
 	   .flatMap (child =>
-	      renderTagTree (child, nestLevel + 1, key, suppressClickRef, tag.id, sp)))
+	      renderTagTree (
+		  activeDndId,
+		  child,
+		  nestLevel + 1,
+		  key,
+		  suppressClickRef,
+		  tag.id,
+		  sp)))
 	  ?? [])]
 }
 
-
-const flattenTagTree = (
-    tags: TagWithSections[],
-): FlatTagRow[] => {
-  const seen = new Set<number> ()
-  const rows: FlatTagRow[] = []
-
-  const visit = (
-      tag:           TagWithSections,
-      parentTagId?:  number,
-  ) => {
-    if (seen.has (tag.id))
-      return
-
-    seen.add (tag.id)
-    rows.push ({ tag, parentTagId })
-
-    for (const child of tag.children ?? [])
-      visit (child, tag.id)
-  }
-
-  for (const tag of tags)
-    visit (tag)
-
-  return rows.sort ((rowA, rowB) => rowA.tag.name < rowB.tag.name ? -1 : 1)
-}
-
-
 const isDescendant = (
     root:     TagWithSections,
     targetId: number,
@@ -158,6 +146,37 @@ const buildTagByCategory = (post: Post): TagByCategory => {
 }
 
 
+const buildFlatTagByCategory = (
+    byCategory: TagByCategory,
+): TagByCategory => {
+  const tagsTmp = { } as TagByCategory
+  const seen = new Set<number> ()
+
+  for (const category of CATEGORIES)
+    tagsTmp[category] = []
+
+  const visit = (tag: TagWithSections) => {
+    if (seen.has (tag.id))
+      return
+
+    seen.add (tag.id)
+    tagsTmp[tag.category].push ({ ...tag, children: [] })
+
+    for (const child of tag.children ?? [])
+      visit (child)
+  }
+
+  for (const category of CATEGORIES)
+    for (const tag of byCategory[category] ?? [])
+      visit (tag)
+
+  for (const category of CATEGORIES)
+    tagsTmp[category].sort ((tagA, tagB) => tagA.name < tagB.name ? -1 : 1)
+
+  return tagsTmp
+}
+
+
 const changeCategory = async (
     tagId:    number,
     category: Category): Promise<void> => {
@@ -176,12 +195,35 @@ const DropSlot = ({ cat }: { cat: Category }) => {
       </li>)
 }
 
+const EmptyCategoryDropSection = (
+    { cat, children }: { cat: Category
+			 children: ReactNode }) => {
+  const { setNodeRef, isOver: over } = useDroppable ({
+      id:   `slot:${ cat }`,
+      data: { kind: 'slot', cat } })
+
+  return (
+      <div ref={setNodeRef} className="my-3">
+	{children}
+	<ul>
+	  <li className="h-1">
+	    {over && <div className="h-0.5 w-full rounded bg-sky-400"/>}
+	  </li>
+	</ul>
+      </div>)
+}
+
 
 type Props = {
     className?: string
     post:       Post
     sp?:        boolean }
 
+type ActiveTagDrag = {
+    dndId:       string
+    tagId:      number
+    nestLevel:  number }
+
 
 const TagDetailSidebar: FC<Props> = ({ className, post, sp }) => {
   sp = Boolean (sp)
@@ -189,6 +231,11 @@ const TagDetailSidebar: FC<Props> = ({ className, post, sp }) => {
   const qc = useQueryClient ()
   const behaviourSettings = useClientBehaviourSettings ()
   const tagRelationDisplay = behaviourSettings.tagRelationDisplay ?? 'grouped'
+  const animationMode = behaviourSettings.animation ?? 'normal'
+  const layoutTransition = clientAnimationTransition (
+      animationMode,
+      { normal: { duration: .2, ease: 'easeOut' as const } },
+  )
 
   const baseTags = useMemo<TagByCategory> (() => {
     const tagsTmp = { } as TagByCategory
@@ -206,10 +253,15 @@ const TagDetailSidebar: FC<Props> = ({ className, post, sp }) => {
     return tagsTmp
   }, [post])
 
-  const [activeTagId, setActiveTagId] = useState<number | null> (null)
+  const [activeTagDrag, setActiveTagDrag] = useState<ActiveTagDrag | null> (null)
   const [dragging, setDragging] = useState (false)
   const [saving, setSaving] = useState (false)
   const [tags, setTags] = useState (baseTags)
+  const flatTagsByCategory = useMemo<TagByCategory> (
+      () => buildFlatTagByCategory (tags),
+      [tags],
+  )
+  const activeDndId = activeTagDrag?.dndId
 
   const suppressClickRef = useRef (false)
 
@@ -318,9 +370,19 @@ const TagDetailSidebar: FC<Props> = ({ className, post, sp }) => {
 	<TagSearch/>
 	<DndContext
 	    sensors={sensors}
+	    collisionDetection={tagCollisionDetection}
+	    measuring={alwaysMeasureDroppables}
 	    onDragStart={e => {
 	      if (e.active.data.current?.kind === 'tag')
-		setActiveTagId (e.active.data.current?.tagId ?? null)
+		{
+		  const tagId = e.active.data.current?.tagId
+		  const nestLevel = e.active.data.current?.nestLevel
+		  const dndId = e.active.data.current?.dndId
+		  setActiveTagDrag (
+		      tagId == null || nestLevel == null || dndId == null
+		      ? null
+		      : { dndId, tagId, nestLevel })
+		}
 	      setDragging (true)
 	      suppressClickRef.current = true
 	      document.body.style.userSelect = 'none'
@@ -331,57 +393,80 @@ const TagDetailSidebar: FC<Props> = ({ className, post, sp }) => {
 		suppressClickRef.current = false}, { capture: true, once: true })
 	    }}
 	    onDragCancel={() => {
-	      setActiveTagId (null)
+	      setActiveTagDrag (null)
 	      setDragging (false)
 	      document.body.style.userSelect = ''
 	      suppressClickRef.current = false
 	    }}
 	    onDragEnd={async e => {
-	      setActiveTagId (null)
+	      setActiveTagDrag (null)
 	      setDragging (false)
 	      await onDragEnd (e)
 	      document.body.style.userSelect = ''
 	    }}
 	    modifiers={[restrictToWindowEdges]}>
-	  {CATEGORIES.map ((cat: Category) => ((tags[cat] ?? []).length > 0 || dragging) && (
-	      <div className="my-3" key={cat}>
+	  {CATEGORIES.map ((cat: Category) => {
+	    const categoryTags =
+		tagRelationDisplay === 'grouped'
+		? (tags[cat] ?? [])
+		: (flatTagsByCategory[cat] ?? [])
+
+	    if (!(categoryTags.length > 0 || dragging))
+	      return null
+
+	    const sectionTitle = (
 		<SubsectionTitle>
 		  <motion.div
-		      layoutId={`tag-${ sp ? 'sp-' : '' }${ cat }`}
-		      transition={{ layout: { duration: .2, ease: 'easeOut' } }}>
+		      layoutId={animationMode === 'off'
+			  ? undefined
+			  : `tag-${ sp ? 'sp-' : '' }${ cat }`}
+		      transition={{ layout: layoutTransition }}>
 		    {CATEGORY_NAMES[cat]}
 		  </motion.div>
-		</SubsectionTitle>
+		</SubsectionTitle>)
 
-		<ul>
-		  {(tagRelationDisplay === 'grouped'
-		    ? (tags[cat] ?? []).flatMap (tag =>
-			  renderTagTree (
-			      tag,
-			      0,
-			      `cat-${ cat }`,
-			      suppressClickRef,
-			      undefined,
-			      sp,
-			  ),
-		      )
-		    : flattenTagTree (tags[cat] ?? []).map (row => (
-			<li key={`flat-${ cat }-${ row.tag.id }`} className="mb-1">
-			  <DraggableDroppableTagRow
-			      tag={row.tag}
-			      nestLevel={0}
-			      pathKey={`flat-${ cat }-${ row.tag.id }`}
-			      parentTagId={row.parentTagId}
-			      suppressClickRef={suppressClickRef}
-			      sp={sp}/>
-			</li>)))}
-		  <DropSlot cat={cat}/>
-		</ul>
-	      </div>))}
+	    if (!(categoryTags.length > 0))
+	      return (
+		  <EmptyCategoryDropSection cat={cat} key={cat}>
+		    {sectionTitle}
+		  </EmptyCategoryDropSection>)
+
+	    return (
+		<div className="my-3" key={cat}>
+		  {sectionTitle}
+		  <ul>
+		    {(tagRelationDisplay === 'grouped'
+		      ? (tags[cat] ?? []).flatMap (tag =>
+			    renderTagTree (
+				activeDndId,
+				tag,
+				0,
+				`cat-${ cat }`,
+				suppressClickRef,
+				undefined,
+				sp,
+			    ),
+			)
+		      : (flatTagsByCategory[cat] ?? []).map (tag => (
+			  <li key={`flat-${ cat }-${ tag.id }`} className="mb-1">
+			    <DraggableDroppableTagRow
+				activeDndId={activeDndId}
+				tag={tag}
+				nestLevel={0}
+				pathKey={`flat-${ cat }-${ tag.id }`}
+				suppressClickRef={suppressClickRef}
+				sp={sp}/>
+			  </li>)))}
+		    <DropSlot cat={cat}/>
+		  </ul>
+		</div>)
+	  })}
 	  {post && (
 	      <motion.div
-		  layoutId={`post-info-${ sp }`}
-		  transition={{ layout: { duration: .2, ease: 'easeOut' } }}>
+		  layoutId={animationMode === 'off'
+		      ? undefined
+		      : `post-info-${ sp }`}
+		  transition={{ layout: layoutTransition }}>
 		<SectionTitle>情報</SectionTitle>
 		<ul>
 		  <li>Id.: {post.id}</li>
@@ -418,11 +503,14 @@ const TagDetailSidebar: FC<Props> = ({ className, post, sp }) => {
 		</ul>
 	      </motion.div>)}
 
-	  <DragOverlay adjustScale={false}>
+	  <DragOverlay
+	      adjustScale={false}
+	      modifiers={[snapCenterToCursor]}
+	      dropAnimation={animationMode === 'off' ? null : undefined}>
 	    <div className="pointer-events-none">
-	      {activeTagId != null && (() => {
-		const tag = findTag (tags, activeTagId)
-		return tag && <TagLink tag={tag}/>
+	      {activeTagDrag != null && (() => {
+		const tag = findTag (tags, activeTagDrag.tagId)
+		return tag && <TagLink tag={tag} nestLevel={activeTagDrag.nestLevel}/>
 	      }) ()}
 	    </div>
 	  </DragOverlay>

frontend/src/components/TagSidebar.tsx

@@ -8,6 +8,8 @@ import SectionTitle from '@/components/common/SectionTitle'
 import SidebarComponent from '@/components/layout/SidebarComponent'
 import { CATEGORIES } from '@/consts'
 import { apiGet } from '@/lib/api'
+import { clientAnimationTransition } from '@/lib/clientAnimation'
+import { useClientBehaviourSettings } from '@/lib/useClientBehaviourSettings'
 
 import type { FC, MouseEvent } from 'react'
 
@@ -21,6 +23,13 @@ type Props = { posts:     Post[]
 
 const TagSidebar: FC<Props> = ({ posts, onClick }) => {
   const navigate = useNavigate ()
+  const behaviourSettings = useClientBehaviourSettings ()
+  const animationMode = behaviourSettings.animation ?? 'normal'
+  const animationsOff = animationMode === 'off'
+  const layoutTransition = clientAnimationTransition (
+      animationMode,
+      { normal: { duration: .2, ease: 'easeOut' as const } },
+  )
 
   const [tagsVsbl, setTagsVsbl] = useState (false)
   const [tags, setTags] = useState<TagByCategory> ({ })
@@ -65,12 +74,18 @@ const TagSidebar: FC<Props> = ({ posts, onClick }) => {
 	  {CATEGORIES.flatMap (cat => cat in tags ? (
 	      tags[cat].map (tag => (
 		  <li key={tag.id} className="mb-1 min-w-0 max-w-full overflow-hidden">
-		    <motion.div
-			className="flex min-w-0 max-w-full items-baseline overflow-hidden"
-			transition={{ layout: { duration: .2, ease: 'easeOut' } }}
-			layoutId={`tag-${ tag.id }`}>
-		      <TagLink tag={tag} onClick={onClick}/>
-		    </motion.div>
+		    {animationsOff
+		     ? (
+			 <div className="flex min-w-0 max-w-full items-baseline overflow-hidden">
+			   <TagLink tag={tag} onClick={onClick}/>
+			 </div>)
+		     : (
+			 <motion.div
+			     className="flex min-w-0 max-w-full items-baseline overflow-hidden"
+			     transition={{ layout: layoutTransition }}
+			     layoutId={`tag-${ tag.id }`}>
+			   <TagLink tag={tag} onClick={onClick}/>
+			 </motion.div>)}
 		  </li>))) : [])}
 	</ul>
 	<SectionTitle>関聯</SectionTitle>
@@ -103,18 +118,25 @@ const TagSidebar: FC<Props> = ({ posts, onClick }) => {
 	  {posts.length > 0 && TagBlock}
 	</div>
 
-	<AnimatePresence initial={false}>
-	  {tagsVsbl && (
-	      <motion.div
-		  key="sptags"
-		  className="md:hidden overflow-hidden"
-		  initial={{ height: 0 }}
-		  animate={{ height: 'auto' }}
-		  exit={{ height: 0 }}
-		  transition={{ duration: .2, ease: 'easeOut' }}>
-		{posts.length > 0 && TagBlock}
-	      </motion.div>)}
-	</AnimatePresence>
+	{animationsOff
+	 ? (
+	     tagsVsbl && (
+		 <div className="md:hidden overflow-hidden">
+		   {posts.length > 0 && TagBlock}
+		 </div>))
+	 : (
+	     <AnimatePresence initial={false}>
+	       {tagsVsbl && (
+		   <motion.div
+		       key="sptags"
+		       className="md:hidden overflow-hidden"
+		       initial={{ height: 0 }}
+		       animate={{ height: 'auto' }}
+		       exit={{ height: 0 }}
+		       transition={layoutTransition}>
+		     {posts.length > 0 && TagBlock}
+		   </motion.div>)}
+	     </AnimatePresence>)}
 
 	<a href="#"
 	   className="md:hidden block my-2 text-center text-sm

frontend/src/components/TopNav.tsx

@@ -161,13 +161,17 @@ const TopNav: FC<Props> = ({ user }) => {
       visibleMenu.findIndex (item => location.pathname.startsWith (item.base || item.to))
   const submenuHeight = moreVsbl ? 40 * moreMenu.length : (activeIdx < 0 ? 0 : 40)
   const topNavTransition =
-      reducedAnimations
-      ? { duration: .08, ease: 'linear' as const }
-      : { duration: .2, ease: 'easeOut' as const }
+      animationsOff
+      ? { duration: 0 }
+      : reducedAnimations
+	? { duration: .08, ease: 'linear' as const }
+	: { duration: .2, ease: 'easeOut' as const }
   const opacityTransition =
-      reducedAnimations
-      ? { duration: .08 }
-      : { duration: .12 }
+      animationsOff
+      ? { duration: 0 }
+      : reducedAnimations
+	? { duration: .08 }
+	: { duration: .12 }
   const highlightTransitionClass =
       animationsOff
       ? undefined

frontend/src/components/common/TabGroup.test.tsx

@@ -20,4 +20,16 @@ describe ('TabGroup', () => {
     expect (screen.getByText ('Alpha')).toBeInTheDocument ()
     expect (screen.queryByText ('Beta')).not.toBeInTheDocument ()
   })
+
+  it ('renders tabs as buttons and shows the right addon', () => {
+    render (
+        <TabGroup rightAddon={<span>件数 20</span>}>
+          <Tab name="広場">Plaza</Tab>
+        </TabGroup>,
+    )
+
+    expect (screen.getByRole ('button', { name: '広場' })).toBeInTheDocument ()
+    expect (screen.queryByRole ('link', { name: '広場' })).not.toBeInTheDocument ()
+    expect (screen.getByText ('件数 20')).toBeInTheDocument ()
+  })
 })

frontend/src/components/layout/MainArea.tsx

@@ -1,5 +1,7 @@
 import { motion } from 'framer-motion'
 
+import { clientAnimationTransition } from '@/lib/clientAnimation'
+import { useClientBehaviourSettings } from '@/lib/useClientBehaviourSettings'
 import { cn } from '@/lib/utils'
 
 import type { FC, ReactNode } from 'react'
@@ -9,12 +11,21 @@ type Props = {
     className?: string }
 
 
-const MainArea: FC<Props> = ({ children, className }) => (
-    <motion.main
-	transition={{ layout: { duration: .2, ease: 'easeOut' } }}
-	className={cn ('flex-1 overflow-y-auto p-4', className)}
-	layout="position">
-      {children}
-    </motion.main>)
+const MainArea: FC<Props> = ({ children, className }) => {
+  const behaviourSettings = useClientBehaviourSettings ()
+  const animationMode = behaviourSettings.animation ?? 'normal'
+  const layoutTransition = clientAnimationTransition (
+      animationMode,
+      { normal: { duration: .2, ease: 'easeOut' as const } },
+  )
+
+  return (
+      <motion.main
+	  transition={{ layout: layoutTransition }}
+	  className={cn ('flex-1 overflow-y-auto p-4', className)}
+	  layout={animationMode === 'off' ? false : 'position'}>
+	{children}
+      </motion.main>)
+}
 
 export default MainArea

frontend/src/components/layout/SidebarComponent.tsx

@@ -1,6 +1,8 @@
 import { motion } from 'framer-motion'
 import { Helmet } from 'react-helmet-async'
 
+import { clientAnimationTransition } from '@/lib/clientAnimation'
+import { useClientBehaviourSettings } from '@/lib/useClientBehaviourSettings'
 import { cn } from '@/lib/utils'
 
 import type { CSSProperties, FC, MouseEvent, PointerEvent, ReactNode } from 'react'
@@ -68,6 +70,12 @@ const SidebarComponent: FC<Props> = ({
     sidebarKey,
     side = 'left',
 }) => {
+  const behaviourSettings = useClientBehaviourSettings ()
+  const animationMode = behaviourSettings.animation ?? 'normal'
+  const layoutTransition = clientAnimationTransition (
+      animationMode,
+      { normal: { duration: .2, ease: 'easeOut' as const } },
+  )
   const rootRef = useRef<HTMLDivElement | null> (null)
   const maxWidthRef = useRef (maxWidth)
   const getContainerWidth = useCallback (() => {
@@ -305,8 +313,8 @@ const SidebarComponent: FC<Props> = ({
   return (
       <motion.div
 	  ref={rootRef}
-	  layout="position"
-	  transition={{ layout: { duration: .2, ease: 'easeOut' } }}
+	  layout={animationMode === 'off' ? false : 'position'}
+	  transition={{ layout: layoutTransition }}
 	  style={style}
 	  className={cn (
 	      'relative w-full md:w-[var(--sidebar-width)] md:shrink-0 md:h-full',

frontend/src/components/users/BehaviourSettingsSection.tsx

@@ -11,8 +11,7 @@ import type { ClientAnimationMode,
 	      ClientBehaviorSettings,
 	      ClientEmbedAutoLoadMode,
 	      ClientLinkPreloadMode,
-	      ClientTagRelationDisplayMode,
-	      ClientThumbnailMode } from '@/lib/settings'
+	      ClientTagRelationDisplayMode } from '@/lib/settings'
 
 type Props = {
     sectionClassName: string
@@ -31,9 +30,9 @@ type SegmentedControlProps<T extends string> = {
     onChange:  (value: T) => void }
 
 type SettingBlockProps = {
-    title:       string
-    description: string
-    children:    ReactNode }
+    title:        string
+    description?: string
+    children:     ReactNode }
 
 const animationOptions: SegmentedOption<ClientAnimationMode>[] = [
     { value: 'off', label: 'なし' },
@@ -47,18 +46,12 @@ const embedAutoLoadOptions: SegmentedOption<ClientEmbedAutoLoadMode>[] = [
 
 const linkPreloadOptions: SegmentedOption<ClientLinkPreloadMode>[] = [
     { value: 'off', label: 'しない' },
-    { value: 'intent', label: 'マウスを置いたら' }]
+    { value: 'intent', label: 'する' }]
 
 const tagRelationDisplayOptions: SegmentedOption<ClientTagRelationDisplayMode>[] = [
     { value: 'flat', label: 'まとめない' },
     { value: 'grouped', label: 'まとめる' }]
 
-const thumbnailModeOptions: SegmentedOption<ClientThumbnailMode>[] = [
-    { value: 'off', label: '非表示' },
-    { value: 'light', label: '軽量' },
-    { value: 'normal', label: '通常' }]
-
-
 const SegmentedControl = <T extends string,> (
     { value, options, onChange }: SegmentedControlProps<T>,
 ) => {
@@ -90,7 +83,7 @@ const SegmentedControl = <T extends string,> (
 const SettingBlock: FC<SettingBlockProps> = (
     { title, description, children },
 ) => (
-    <div className="space-y-3 rounded-xl border border-border/70 bg-background/70 p-4">
+    <div className="space-y-3 rounded-xl px-4">
       <div className="space-y-1">
 	<h3 className="text-sm font-semibold">{title}</h3>
 	<p className="text-sm text-muted-foreground">{description}</p>
@@ -149,16 +142,12 @@ const BehaviourSettingsSection: FC<Props> = (
 	<div className="flex flex-wrap items-start justify-between gap-3">
 	  <div className="space-y-1">
 	    <h2 className="text-xl font-bold">動作</h2>
-	    {hasUnsavedChanges && (
-		<p className="text-sm text-amber-700 dark:text-amber-300">
-		  未保存の変更があります
-		</p>)}
 	  </div>
 
 	  <div className="flex flex-wrap gap-2">
 	    <Button
 		type="button"
-		variant="outline"
+		variant="destructive"
 		disabled={hasUnsavedChanges === false}
 		onClick={handleDiscard}>
 	      変更を破棄
@@ -173,9 +162,7 @@ const BehaviourSettingsSection: FC<Props> = (
 	</div>
 
 	<div className="space-y-4">
-	  <SettingBlock
-	      title="アニメーション"
-	      description="画面遷移やレイアウト移動の動きを調整します。">
+	  <SettingBlock title="アニメーション">
 	    <SegmentedControl
 		value={draftSettings.animation ?? 'normal'}
 		options={animationOptions}
@@ -184,39 +171,26 @@ const BehaviourSettingsSection: FC<Props> = (
 
 	  <SettingBlock
 	      title="リンク先の先読み"
-	      description="リンクにマウスを置いた時などに、移動先の情報を先に読みます。通信量や意図しない読込みが気になる場合は「しない」にできます。">
+	      description="マウスを置いた時点でリンク先のデータを取得します。">
 	    <SegmentedControl
 		value={draftSettings.linkPreload ?? 'intent'}
 		options={linkPreloadOptions}
 		onChange={value => updateDraft ('linkPreload', value)}/>
 	  </SettingBlock>
 
-	  <SettingBlock
-	      title="タグの親子関係表示"
-	      description="親子関係があるタグを、まとまりとして表示します。見た目を単純にしたい場合は「まとめない」にできます。">
+	  <SettingBlock title="タグの親子関係表示">
 	    <SegmentedControl
 		value={draftSettings.tagRelationDisplay ?? 'grouped'}
 		options={tagRelationDisplayOptions}
 		onChange={value => updateDraft ('tagRelationDisplay', value)}/>
 	  </SettingBlock>
 
-	  <SettingBlock
-	      title="埋め込み自動読込"
-	      description="外部埋め込みを自動で読み込むかを切り替えます。">
+	  <SettingBlock title="埋め込み自動読込">
 	    <SegmentedControl
 		value={draftSettings.embedAutoLoad ?? 'auto'}
 		options={embedAutoLoadOptions}
 		onChange={value => updateDraft ('embedAutoLoad', value)}/>
 	  </SettingBlock>
-
-	  <SettingBlock
-	      title="サムネイル表示"
-	      description="投稿一覧や詳細の画像表示を軽量化します。">
-	    <SegmentedControl
-		value={draftSettings.thumbnailMode ?? 'normal'}
-		options={thumbnailModeOptions}
-		onChange={value => updateDraft ('thumbnailMode', value)}/>
-	  </SettingBlock>
 	</div>
       </section>)
 }

frontend/src/components/users/KeyboardSettingsSection.tsx

@@ -147,10 +147,6 @@ const KeyboardSettingsSection: FC<Props> = (
 	<div className="flex flex-wrap items-start justify-between gap-3">
 	  <div className="space-y-1">
 	    <h2 className="text-xl font-bold">キーボード</h2>
-	    {hasUnsavedChanges && (
-		<p className="text-sm text-amber-700 dark:text-amber-300">
-		  未保存の変更があります
-		</p>)}
 	  </div>
 
 	  <div className="flex flex-wrap gap-2">
@@ -167,7 +163,7 @@ const KeyboardSettingsSection: FC<Props> = (
 	    </Button>
 	    <Button
 		type="button"
-		variant="outline"
+		variant="destructive"
 		disabled={!(hasUnsavedChanges)}
 		onClick={handleDiscard}>
 	      変更を破棄
@@ -206,8 +202,8 @@ const KeyboardSettingsSection: FC<Props> = (
 		<th className="p-2 text-left">操作</th>
 		<th className="p-2 text-left">適用範囲</th>
 		<th className="p-2 text-left">現在のキー</th>
-		<th className="p-2 text-left">変更</th>
-		<th className="p-2 text-left">既定に戻す</th>
+		<th className="p-2 text-left"></th>
+		<th className="p-2 text-left"></th>
 		<th className="p-2 text-left">競合状態</th>
 	      </tr>
 	    </thead>

frontend/src/components/users/UserSettingsProvider.tsx

@@ -1,97 +0,0 @@
-import { createContext, useContext, useEffect, useMemo, useState } from 'react'
-
-import {
-    applyClientAppearance,
-    DEFAULT_USER_SETTINGS,
-    fetchUserSettings,
-} from '@/lib/settings'
-
-import type { Dispatch, FC, ReactNode, SetStateAction } from 'react'
-
-import type { User } from '@/types'
-import type { UserSettings } from '@/lib/settings'
-
-type ContextValue = {
-    loaded:       boolean
-    error:        string | null
-    settings:     UserSettings
-    setSettings:  Dispatch<SetStateAction<UserSettings>> }
-
-const UserSettingsContext = createContext<ContextValue | null> (null)
-
-
-export const UserSettingsProvider: FC<{
-    children:  ReactNode
-    user:      User | null }> = ({ children, user }) => {
-  const [error, setError] = useState<string | null> (null)
-  const [loaded, setLoaded] = useState (false)
-  const [settings, setSettings] = useState<UserSettings> (DEFAULT_USER_SETTINGS)
-
-  useEffect (() => {
-    let cancelled = false
-
-    if (!(user))
-      {
-	setError (null)
-	setSettings (DEFAULT_USER_SETTINGS)
-	setLoaded (true)
-	return
-      }
-
-    setLoaded (false)
-    setError (null)
-
-    void (async () => {
-      try
-      {
-	const next = await fetchUserSettings ()
-	if (!(cancelled))
-	  {
-	    setError (null)
-	    setSettings (next)
-	    setLoaded (true)
-	  }
-      }
-      catch
-      {
-	if (!(cancelled))
-	  {
-	    setError ('設定を読み込めませんでした．既定値で表示しています．')
-	    setSettings (DEFAULT_USER_SETTINGS)
-	    setLoaded (true)
-	  }
-      }
-    }) ()
-
-    return () => {
-      cancelled = true
-    }
-  }, [user])
-
-  useEffect (() => {
-    void settings.theme
-    applyClientAppearance ()
-  }, [settings.theme])
-
-  const value = useMemo<ContextValue> (() => ({
-      error,
-      loaded,
-      settings,
-      setSettings,
-  }), [error, loaded, settings])
-
-  return (
-      <UserSettingsContext.Provider value={value}>
-	{children}
-      </UserSettingsContext.Provider>)
-}
-
-
-export const useUserSettings = (): ContextValue => {
-  const value = useContext (UserSettingsContext)
-
-  if (value == null)
-    throw new Error ('UserSettingsProvider is missing')
-
-  return value
-}

frontend/src/index.css

@@ -38,6 +38,7 @@
     --top-nav-root-bg-desktop: #fefce8;
     --top-nav-active-bg: #fef08a;
     --top-nav-submenu-bg: #fef08a;
+    --top-nav-mobile-menu-bg: #fef08a;
     --top-nav-mobile-active-bg: #fefce8;
     --top-nav-brand-link: #db2777;
     --top-nav-menu-link: #1d4ed8;
@@ -89,6 +90,7 @@
     --top-nav-root-bg-desktop: #230505;
     --top-nav-active-bg: #450a0a;
     --top-nav-submenu-bg: #450a0a;
+    --top-nav-mobile-menu-bg: #230505;
     --top-nav-mobile-active-bg: #450a0a;
     --top-nav-brand-link: #f9a8d4;
     --top-nav-menu-link: #93c5fd;
@@ -105,7 +107,7 @@
   }
   a:hover
   {
-    opacity: .85;
+    color: color-mix(in oklab, hsl(var(--theme-link)), white 18%);
   }
 }
 
@@ -125,29 +127,6 @@
   -moz-osx-font-smoothing: grayscale;
 }
 
-:root[data-font-size='small']
-{
-  font-size: 14px;
-}
-
-:root[data-font-size='normal']
-{
-  font-size: 16px;
-}
-
-:root[data-font-size='large']
-{
-  font-size: 18px;
-}
-
-:root[data-display-density='compact'] input,
-:root[data-display-density='compact'] textarea,
-:root[data-display-density='compact'] select,
-:root[data-display-density='compact'] button
-{
-  line-height: 1.25;
-}
-
 :root[data-animation='reduced'] *,
 :root[data-animation='off'] *
 {
@@ -158,9 +137,11 @@
 :root[data-animation='off'] *::before,
 :root[data-animation='off'] *::after
 {
-  animation-duration: 0.001ms !important;
+  animation-duration: 0ms !important;
+  animation-delay: 0ms !important;
   animation-iteration-count: 1 !important;
-  transition-duration: 0.001ms !important;
+  transition-duration: 0ms !important;
+  transition-delay: 0ms !important;
 }
 
 a
@@ -260,7 +241,7 @@ body
 
 .top-nav-mobile-menu
 {
-  background: var(--top-nav-root-bg-mobile);
+  background: var(--top-nav-mobile-menu-bg);
 }
 
 .top-nav-mobile-active

frontend/src/lib/clientAnimation.ts

@@ -0,0 +1,34 @@
+import type { Transition } from 'framer-motion'
+
+import type { ClientAnimationMode } from '@/lib/settings'
+
+type ClientAnimationTransitionOptions = {
+    normal:   Transition
+    reduced?: Transition
+    off?:     Transition }
+
+
+export const clientAnimationsOff = (
+    animationMode: ClientAnimationMode,
+): boolean =>
+    animationMode === 'off'
+
+
+export const clientAnimationTransition = (
+    animationMode: ClientAnimationMode,
+    { normal, reduced, off }: ClientAnimationTransitionOptions,
+): Transition => {
+  if (animationMode === 'off')
+    return off ?? { duration: 0 }
+
+  if (animationMode === 'reduced')
+    return reduced ?? { duration: .08, ease: 'linear' as const }
+
+  return normal
+}
+
+
+export const clientScrollBehaviour = (
+    animationMode: ClientAnimationMode,
+): ScrollBehavior =>
+    animationMode === 'off' ? 'auto' : 'smooth'

frontend/src/lib/keyboardShortcuts.test.ts

@@ -0,0 +1,65 @@
+import { describe, expect, it } from 'vitest'
+
+import { DEFAULT_KEY_BINDINGS,
+	 formatKeyBinding,
+	 getConflictingShortcutActionIds,
+	 isEditableEventTarget,
+	 keyBindingFromKeyboardEvent,
+	 resolveShortcutScope,
+	 SHORTCUT_DEFINITIONS_BY_ID } from '@/lib/keyboardShortcuts'
+
+describe ('keyboardShortcuts', () => {
+  it ('defines the default key bindings used by the settings screen', () => {
+    expect (SHORTCUT_DEFINITIONS_BY_ID['global.openShortcutHelp']).toMatchObject ({
+	label: 'ショートカット一覧を開く',
+	scope: 'global',
+	defaultBinding: { key: '?', shift: true } })
+    expect (DEFAULT_KEY_BINDINGS['global.focusSearch']).toEqual ({ key: '/' })
+    expect (DEFAULT_KEY_BINDINGS['navigation.posts']).toEqual ({ key: 'p' })
+    expect (DEFAULT_KEY_BINDINGS['pagination.next']).toEqual ({ key: 'ArrowRight' })
+    expect (DEFAULT_KEY_BINDINGS['settings.theme']).toEqual ({ key: '3' })
+  })
+
+  it ('formats key bindings for display', () => {
+    expect (formatKeyBinding ({ key: '?', shift: true })).toBe ('Shift + ?')
+    expect (formatKeyBinding ({ key: '/' })).toBe ('/')
+    expect (formatKeyBinding ({ key: 'p' })).toBe ('P')
+    expect (formatKeyBinding ({ key: 'ArrowRight' })).toBe ('ArrowRight')
+    expect (formatKeyBinding (null)).toBe ('未割当')
+  })
+
+  it ('normalises keyboard events without assigning space by default', () => {
+    const event = { key: 'P',
+		    ctrlKey: false,
+		    shiftKey: false,
+		    altKey: false,
+		    metaKey: false } as KeyboardEvent
+
+    expect (keyBindingFromKeyboardEvent (event)).toEqual ({ key: 'p' })
+    expect (DEFAULT_KEY_BINDINGS['pagination.next']).not.toEqual ({ key: ' ' })
+  })
+
+  it ('detects conflicting action bindings', () => {
+    const conflicts = getConflictingShortcutActionIds ({
+	...DEFAULT_KEY_BINDINGS,
+	'navigation.posts': { key: 'p' },
+	'navigation.tags': { key: 'p' } })
+
+    expect (conflicts.has ('navigation.posts')).toBe (true)
+    expect (conflicts.has ('navigation.tags')).toBe (true)
+    expect (conflicts.has ('navigation.wiki')).toBe (false)
+  })
+
+  it ('resolves route scopes and editable event targets', () => {
+    const input = document.createElement ('input')
+    const div = document.createElement ('div')
+    div.setAttribute ('role', 'textbox')
+
+    expect (resolveShortcutScope ('/posts/search')).toBe ('postSearch')
+    expect (resolveShortcutScope ('/users/settings')).toBe ('settings')
+    expect (resolveShortcutScope ('/materials/1')).toBe ('materials')
+    expect (isEditableEventTarget (input)).toBe (true)
+    expect (isEditableEventTarget (div)).toBe (true)
+    expect (isEditableEventTarget (document.createElement ('button'))).toBe (false)
+  })
+})

frontend/src/lib/settings.test.ts

@@ -0,0 +1,108 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+
+import { applyClientAnimationMode,
+	 applyThemeTokens,
+	 buildThemeTokens,
+	 CLIENT_SETTINGS_STORAGE_KEY,
+	 DARK_THEME_TOKENS,
+	 DEFAULT_POST_LIST_ORDER,
+	 getClientListLimit,
+	 getClientListOrder,
+	 getClientThemeMode,
+	 LIGHT_THEME_TOKENS,
+	 loadClientSettings,
+	 setClientListSettings,
+	 setClientThemeAppearance } from '@/lib/settings'
+
+import type { FetchPostsOrder } from '@/types'
+
+const installMatchMedia = (matches: boolean) => {
+  Object.defineProperty (window, 'matchMedia', {
+      configurable: true,
+      value: vi.fn ().mockImplementation (() => ({
+	  matches,
+	  addEventListener: vi.fn (),
+	  removeEventListener: vi.fn () })) })
+}
+
+describe ('settings', () => {
+  beforeEach (() => {
+    localStorage.clear ()
+    document.documentElement.removeAttribute ('data-animation')
+    document.documentElement.removeAttribute ('style')
+    document.documentElement.className = ''
+    installMatchMedia (false)
+  })
+
+  it ('stores list settings under the shared client settings key', () => {
+    setClientListSettings ('postSearch', {
+	limit: 50,
+	order: 'title:asc' })
+
+    expect (getClientListLimit ('postSearch')).toBe (50)
+    expect (getClientListOrder<FetchPostsOrder> ('postSearch')).toBe ('title:asc')
+    expect (JSON.parse (localStorage.getItem (CLIENT_SETTINGS_STORAGE_KEY) ?? '{}'))
+	.toMatchObject ({ lists: { postSearch: { limit: 50, order: 'title:asc' } } })
+  })
+
+  it ('ignores invalid list limits and keeps stored order strings', () => {
+    localStorage.setItem (
+	CLIENT_SETTINGS_STORAGE_KEY,
+	JSON.stringify ({ lists: { postList: { limit: 30, order: DEFAULT_POST_LIST_ORDER } } }))
+
+    expect (getClientListLimit ('postList')).toBeNull ()
+    expect (getClientListOrder<FetchPostsOrder> ('postList')).toBe (
+	DEFAULT_POST_LIST_ORDER)
+  })
+
+  it ('stores theme mode and light/dark slot selections in client settings', () => {
+    setClientThemeAppearance ({
+	themeMode: 'dark',
+	activeLightThemeSlotNo: 2,
+	activeDarkThemeSlotNo: 3 })
+
+    expect (getClientThemeMode ()).toBe ('dark')
+    expect (loadClientSettings ().appearance).toMatchObject ({
+	themeMode: 'dark',
+	activeLightThemeSlotNo: 2,
+	activeDarkThemeSlotNo: 3 })
+  })
+
+  it ('applies animation mode to the document dataset', () => {
+    applyClientAnimationMode ('off')
+    expect (document.documentElement.dataset.animation).toBe ('off')
+
+    applyClientAnimationMode ('reduced')
+    expect (document.documentElement.dataset.animation).toBe ('reduced')
+
+    applyClientAnimationMode ('normal')
+    expect (document.documentElement.dataset.animation).toBeUndefined ()
+  })
+
+  it ('normalises TopNav menu link tokens to complete CSS colours', () => {
+    const tokens = buildThemeTokens ('light', {
+	link: '221.2 83.2% 53.3%',
+	topNavMenuLink: '221.2 83.2% 53.3%' })
+
+    expect (tokens.link).toBe ('221.2 83.2% 53.3%')
+    expect (tokens.topNavMenuLink).toBe ('hsl(221.2 83.2% 53.3%)')
+  })
+
+  it ('derives TopNav colours without mixing mobile active backgrounds', () => {
+    expect (buildThemeTokens ('light', { }).topNavMobileActiveBackground).toBe (
+	LIGHT_THEME_TOKENS.topNavRootBackgroundDesktop)
+    expect (buildThemeTokens ('dark', { }).topNavMobileActiveBackground).toBe (
+	DARK_THEME_TOKENS.topNavActiveBackground)
+  })
+
+  it ('sets shadcn tokens and TopNav tokens with their different value formats', () => {
+    const tokens = buildThemeTokens ('dark', { link: '213.1 93.9% 67.8%' })
+
+    applyThemeTokens (tokens)
+
+    expect (document.documentElement.style.getPropertyValue ('--theme-link')).toBe (
+	'213.1 93.9% 67.8%')
+    expect (document.documentElement.style.getPropertyValue ('--top-nav-menu-link')).toBe (
+	'hsl(213.1 93.9% 67.8%)')
+  })
+})

frontend/src/lib/useKeyboardShortcuts.tsx

@@ -25,6 +25,7 @@ import {
     getEffectiveKeyBindings,
     setClientKeyboardSettings,
 } from '@/lib/settings'
+import { useUnsavedChangesGuard } from '@/lib/useUnsavedChangesGuard'
 
 import type {
     KeyBinding,
@@ -96,6 +97,7 @@ const focusSearchTarget = (): void => {
 export const KeyboardShortcutsProvider = ({ children }: PropsWithChildren) => {
   const location = useLocation ()
   const navigate = useNavigate ()
+  const { confirmDiscardNavigation } = useUnsavedChangesGuard ()
 
   const [keyboardSettings, setKeyboardSettingsState] =
       useState<ClientKeyboardSettings> (() => getClientKeyboardSettings ())
@@ -146,6 +148,13 @@ export const KeyboardShortcutsProvider = ({ children }: PropsWithChildren) => {
     }
   }, [])
 
+  const guardedNavigate = useCallback ((path: string) => {
+    confirmDiscardNavigation ().then (confirmed => {
+      if (confirmed)
+	navigate (path)
+    })
+  }, [confirmDiscardNavigation, navigate])
+
   const builtinHandlers = useMemo<ShortcutHandlers> (
       () => ({
 	  'global.openShortcutHelp': () => {
@@ -154,16 +163,16 @@ export const KeyboardShortcutsProvider = ({ children }: PropsWithChildren) => {
 	  'global.focusSearch': () => {
 	    focusSearchTarget ()
 	  },
-	  'navigation.posts': () => navigate ('/posts'),
-	  'navigation.tags': () => navigate ('/tags'),
-	  'navigation.materials': () => navigate ('/materials'),
-	  'navigation.wiki': () => navigate ('/wiki'),
-	  'settings.account': () => navigate ('/users/settings?tab=account'),
-	  'settings.theme': () => navigate ('/users/settings?tab=theme'),
-	  'settings.keyboard': () => navigate ('/users/settings?tab=keyboard'),
-	  'settings.behavior': () => navigate ('/users/settings?tab=behavior'),
+	  'navigation.posts': () => guardedNavigate ('/posts'),
+	  'navigation.tags': () => guardedNavigate ('/tags'),
+	  'navigation.materials': () => guardedNavigate ('/materials'),
+	  'navigation.wiki': () => guardedNavigate ('/wiki'),
+	  'settings.account': () => guardedNavigate ('/users/settings?tab=account'),
+	  'settings.theme': () => guardedNavigate ('/users/settings?tab=theme'),
+	  'settings.keyboard': () => guardedNavigate ('/users/settings?tab=keyboard'),
+	  'settings.behavior': () => guardedNavigate ('/users/settings?tab=behavior'),
       }),
-      [navigate],
+      [guardedNavigate],
   )
 
   const availableActionIds = useMemo<Set<ShortcutActionId>> (
@@ -282,10 +291,27 @@ export const useKeyboardShortcutSettings = (): KeyboardShortcutsContextValue =>
 
 export const useKeyboardShortcuts = (handlers: ShortcutHandlers): void => {
   const { registerHandlers } = useKeyboardShortcutSettings ()
+  const handlersRef = useRef (handlers)
+  const actionIdsKey = Object.keys (handlers).sort ().join ('|')
+
+  useEffect (() => {
+    handlersRef.current = handlers
+  }, [handlers])
+
+  const stableHandlers = useMemo<ShortcutHandlers> (() => {
+    return actionIdsKey.split ('|').filter (actionId => actionId !== '')
+	.reduce<ShortcutHandlers> ((nextHandlers, actionId) => {
+	  const key = actionId as ShortcutActionId
+	  nextHandlers[key] = () => {
+	    handlersRef.current[key]?.()
+	  }
+	  return nextHandlers
+	}, { })
+  }, [actionIdsKey])
 
   useEffect (
-      () => registerHandlers (handlers),
-      [handlers, registerHandlers],
+      () => registerHandlers (stableHandlers),
+      [registerHandlers, stableHandlers],
   )
 }
 

frontend/src/lib/useUnsavedChangesGuard.tsx

@@ -0,0 +1,69 @@
+import { createContext, useCallback, useContext, useMemo, useState } from 'react'
+
+import { useDialogue } from '@/components/dialogues/DialogueProvider'
+
+import type { FC, PropsWithChildren } from 'react'
+
+type UnsavedChangesSource = {
+    dirty:    boolean
+    discard:  () => void | Promise<void> }
+
+type UnsavedChangesGuardContextValue = {
+    hasUnsavedChanges:             boolean
+    registerUnsavedChangesSource:  (
+	source: UnsavedChangesSource | null,
+    ) => void
+    confirmDiscardNavigation:      () => Promise<boolean> }
+
+const UnsavedChangesGuardContext =
+    createContext<UnsavedChangesGuardContextValue | null> (null)
+
+
+export const UnsavedChangesGuardProvider: FC<PropsWithChildren> = ({ children }) => {
+  const dialogue = useDialogue ()
+  const [source, setSource] = useState<UnsavedChangesSource | null> (null)
+
+  const registerUnsavedChangesSource = useCallback ((
+      nextSource: UnsavedChangesSource | null,
+  ) => {
+    setSource (nextSource)
+  }, [])
+
+  const confirmDiscardNavigation = useCallback (async (): Promise<boolean> => {
+    if (!(source?.dirty))
+      return true
+
+    const confirmed = await dialogue.confirm ({
+	title: '未保存の変更があります',
+	description: 'このまま移動すると、保存していない変更は失われます。',
+	cancelText: 'このページに残る',
+	confirmText: '変更を破棄して移動',
+	variant: 'danger' })
+    if (!(confirmed))
+      return false
+
+    await source.discard ()
+    return true
+  }, [dialogue, source])
+
+  const value = useMemo<UnsavedChangesGuardContextValue> (() => ({
+      hasUnsavedChanges: source?.dirty === true,
+      registerUnsavedChangesSource,
+      confirmDiscardNavigation,
+  }), [confirmDiscardNavigation, registerUnsavedChangesSource, source?.dirty])
+
+  return (
+      <UnsavedChangesGuardContext.Provider value={value}>
+	{children}
+      </UnsavedChangesGuardContext.Provider>)
+}
+
+
+export const useUnsavedChangesGuard = (): UnsavedChangesGuardContextValue => {
+  const context = useContext (UnsavedChangesGuardContext)
+
+  if (context == null)
+    throw new Error ('UnsavedChangesGuardProvider が必要です．')
+
+  return context
+}

frontend/src/pages/GekanatorPage.tsx

@@ -28,6 +28,7 @@ import {
   getClientGekanatorBackgroundMotion,
   setClientGekanatorBackgroundMotion,
 } from '@/lib/settings'
+import { useClientBehaviourSettings } from '@/lib/useClientBehaviourSettings'
 import { cn } from '@/lib/utils'
 
 import type { FC } from 'react'
@@ -3677,6 +3678,8 @@ const expectedAnswerFor = (
 
 
 const GekanatorPage: FC<{ user: User | null }> = ({ user }) => {
+  const behaviourSettings = useClientBehaviourSettings ()
+  const animationMode = behaviourSettings.animation ?? 'normal'
   const storedGame = useMemo (loadStoredGame, [])
   const hasStoredRestore = storedGame != null && isStoredPhase (storedGame.phase)
   const queryClient = useQueryClient ()
@@ -4069,9 +4072,12 @@ const GekanatorPage: FC<{ user: User | null }> = ({ user }) => {
     return reviewGuessedPostId === reviewCorrectPostId
   }) ()
   const effectiveBackgroundMotionMode = (() => {
+    if (animationMode === 'off')
+      return 'off'
+
     if (backgroundMotionMode === 'off')
       return 'off'
-    if (prefersReducedMotion)
+    if (animationMode === 'reduced' || prefersReducedMotion)
       return 'calm'
 
     return backgroundMotionMode

frontend/src/pages/materials/MaterialHistoryPage.tsx

@@ -9,14 +9,18 @@ import PageTitle from '@/components/common/PageTitle'
 import Pagination from '@/components/common/Pagination'
 import MainArea from '@/components/layout/MainArea'
 import { SITE_TITLE } from '@/config'
+import { clientScrollBehaviour } from '@/lib/clientAnimation'
 import { fetchMaterialChanges } from '@/lib/materials'
 import { materialsKeys } from '@/lib/queryKeys'
+import { useClientBehaviourSettings } from '@/lib/useClientBehaviourSettings'
 import { dateString, inputClass } from '@/lib/utils'
 
 import type { FC, FormEvent } from 'react'
 
 
 const MaterialHistoryPage: FC = () => {
+  const behaviourSettings = useClientBehaviourSettings ()
+  const animationMode = behaviourSettings.animation ?? 'normal'
   const location = useLocation ()
   const navigate = useNavigate ()
   const query = new URLSearchParams (location.search)
@@ -55,8 +59,9 @@ const MaterialHistoryPage: FC = () => {
   const totalPages = data ? Math.ceil (data.count / limit) : 0
 
   useEffect (() => {
-    document.querySelector ('table')?.scrollIntoView ({ behavior: 'smooth' })
-  }, [location.search])
+    document.querySelector ('table')?.scrollIntoView ({
+	behavior: clientScrollBehaviour (animationMode) })
+  }, [animationMode, location.search])
 
   const handleSearch = (event: FormEvent) => {
     event.preventDefault ()

frontend/src/pages/posts/PostHistoryPage.tsx

@@ -12,9 +12,12 @@ 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 { clientAnimationTransition,
+	 clientScrollBehaviour } from '@/lib/clientAnimation'
 import { fetchPostChanges, updatePost } from '@/lib/posts'
 import { postsKeys, tagsKeys } from '@/lib/queryKeys'
 import { fetchTag } from '@/lib/tags'
+import { useClientBehaviourSettings } from '@/lib/useClientBehaviourSettings'
 import { cn, dateString, originalCreatedAtString } from '@/lib/utils'
 
 import type { FC, MouseEvent } from 'react'
@@ -37,6 +40,12 @@ const renderDiff = (diff: { current: string | null; prev: string | null }) => (
 
 const PostHistoryPage: FC = () => {
   const dialogue = useDialogue ()
+  const behaviourSettings = useClientBehaviourSettings ()
+  const animationMode = behaviourSettings.animation ?? 'normal'
+  const layoutTransition = clientAnimationTransition (
+      animationMode,
+      { normal: { duration: .2, ease: 'easeOut' as const } },
+  )
 
   const location = useLocation ()
   const query = new URLSearchParams (location.search)
@@ -113,8 +122,9 @@ const PostHistoryPage: FC = () => {
   }
 
   useEffect (() => {
-    document.querySelector ('table')?.scrollIntoView ({ behavior: 'smooth' })
-  }, [location.search])
+    document.querySelector ('table')?.scrollIntoView ({
+	behavior: clientScrollBehaviour (animationMode) })
+  }, [animationMode, location.search])
 
   const layoutIds: string[] = []
 
@@ -198,8 +208,8 @@ const PostHistoryPage: FC = () => {
 				    rowSpan={rowsCnt}>
 				  <PrefetchLink to={`/posts/${ change.postId }`}>
 				    <motion.div
-					layoutId={layoutId}
-					transition={{ layout: { duration: .2, ease: 'easeOut' } }}>
+					layoutId={animationMode === 'off' ? undefined : layoutId}
+					transition={{ layout: layoutTransition }}>
 				      <img src={change.thumbnail.current
 						|| change.thumbnailBase.current
 						|| undefined}

frontend/src/pages/posts/PostListPage.test.tsx

@@ -1,9 +1,10 @@
 import { fireEvent, screen, waitFor } from '@testing-library/react'
-import { describe, expect, it, vi } from 'vitest'
+import { beforeEach, describe, expect, it, vi } from 'vitest'
 
 import PostListPage from '@/pages/posts/PostListPage'
 import { buildPost, buildTag, buildWikiPage } from '@/test/factories'
 import { renderWithProviders } from '@/test/render'
+import { CLIENT_SETTINGS_STORAGE_KEY } from '@/lib/settings'
 
 const postsApi = vi.hoisted (() => ({
   fetchPosts: vi.fn (),
@@ -18,6 +19,11 @@ vi.mock ('@/lib/posts', () => postsApi)
 vi.mock ('@/lib/wiki', () => wikiApi)
 
 describe ('PostListPage', () => {
+  beforeEach (() => {
+    localStorage.clear ()
+    vi.clearAllMocks ()
+  })
+
   it ('loads posts from the current query and renders the plaza tab', async () => {
     const tag = buildTag ({ name: '虹夏' })
     postsApi.fetchPosts.mockResolvedValueOnce ({
@@ -36,6 +42,7 @@ describe ('PostListPage', () => {
             match: 'all',
             page:  2,
             limit: 20,
+            order: 'original_created_at:desc',
           }),
       )
     })
@@ -71,4 +78,36 @@ describe ('PostListPage', () => {
         '/wiki/%E8%99%B9%E5%A4%8F',
     )
   })
+
+  it ('uses stored list limit but keeps the fixed plaza order', async () => {
+    localStorage.setItem (
+        CLIENT_SETTINGS_STORAGE_KEY,
+        JSON.stringify ({ lists: { postList: { limit: 50, order: 'title:asc' } } }))
+    postsApi.fetchPosts.mockResolvedValueOnce ({ posts: [], count: 0 })
+
+    renderWithProviders (<PostListPage/>, { route: '/posts' })
+
+    await waitFor (() => {
+      expect (postsApi.fetchPosts).toHaveBeenCalledWith (
+          expect.objectContaining ({
+            limit: 50,
+            order: 'original_created_at:desc',
+          }),
+      )
+    })
+  })
+
+  it ('updates the limit from the tab right addon and resets to page 1', async () => {
+    postsApi.fetchPosts.mockResolvedValue ({ posts: [], count: 0 })
+
+    renderWithProviders (<PostListPage/>, { route: '/posts?page=3' })
+
+    fireEvent.change (await screen.findByLabelText ('件数'), { target: { value: '100' } })
+
+    await waitFor (() => {
+      expect (postsApi.fetchPosts).toHaveBeenLastCalledWith (
+          expect.objectContaining ({ page: 1, limit: 100 }),
+      )
+    })
+  })
 })

frontend/src/pages/posts/PostNewPage.test.tsx

@@ -30,16 +30,12 @@ describe ('PostNewPage', () => {
     expect (screen.getByText ('403')).toBeInTheDocument ()
   })
 
-  it ('submits a new post with manual title and thumbnail settings', async () => {
+  it ('submits a new post with manual title and thumbnail fetch UI', async () => {
     api.apiPost.mockResolvedValueOnce ({})
     api.apiGet.mockResolvedValue ([])
 
     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' } })
@@ -97,10 +93,6 @@ describe ('PostNewPage', () => {
 
     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' } })

frontend/src/pages/posts/PostSearchPage.test.tsx

@@ -4,6 +4,7 @@ import { beforeEach, describe, expect, it, vi } from 'vitest'
 import PostSearchPage from '@/pages/posts/PostSearchPage'
 import { buildPost, buildTag } from '@/test/factories'
 import { renderWithProviders } from '@/test/render'
+import { CLIENT_SETTINGS_STORAGE_KEY } from '@/lib/settings'
 
 const postsApi = vi.hoisted (() => ({
   fetchPosts: vi.fn (),
@@ -18,6 +19,7 @@ vi.mock ('@/lib/api', () => api)
 
 describe ('PostSearchPage', () => {
   beforeEach (() => {
+    localStorage.clear ()
     vi.clearAllMocks ()
     api.apiGet.mockResolvedValue ([])
   })
@@ -40,6 +42,7 @@ describe ('PostSearchPage', () => {
             tags:  'x',
             match: 'any',
             page:  2,
+            limit: 20,
           }),
       )
     })
@@ -81,4 +84,41 @@ describe ('PostSearchPage', () => {
 
     expect (await screen.findByText ('結果ないよ（笑）')).toBeInTheDocument ()
   })
+
+  it ('uses URL limit before localStorage and stores the active list settings', async () => {
+    localStorage.setItem (
+        CLIENT_SETTINGS_STORAGE_KEY,
+        JSON.stringify ({ lists: { postSearch: { limit: 100, order: 'title:asc' } } }))
+    postsApi.fetchPosts.mockResolvedValueOnce ({ posts: [], count: 0 })
+
+    renderWithProviders (
+        <PostSearchPage/>,
+        { route: '/posts/search?limit=50&order=created_at%3Adesc' },
+    )
+
+    await waitFor (() => {
+      expect (postsApi.fetchPosts).toHaveBeenCalledWith (
+          expect.objectContaining ({ limit: 50, order: 'created_at:desc' }),
+      )
+    })
+    expect (JSON.parse (localStorage.getItem (CLIENT_SETTINGS_STORAGE_KEY) ?? '{}'))
+        .toMatchObject ({ lists: { postSearch: { limit: 50, order: 'created_at:desc' } } })
+  })
+
+  it ('moves the compact limit control outside the search form and resets page on change', async () => {
+    postsApi.fetchPosts.mockResolvedValue ({ posts: [], count: 0 })
+
+    renderWithProviders (<PostSearchPage/>, { route: '/posts/search?page=4' })
+
+    const limitSelect = await screen.findByLabelText ('件数')
+    expect (limitSelect.closest ('form')).toBeNull ()
+
+    fireEvent.change (limitSelect, { target: { value: '100' } })
+
+    await waitFor (() => {
+      expect (postsApi.fetchPosts).toHaveBeenLastCalledWith (
+          expect.objectContaining ({ page: 1, limit: 100 }),
+      )
+    })
+  })
 })

frontend/src/pages/posts/PostSearchPage.tsx

@@ -14,6 +14,8 @@ import Pagination from '@/components/common/Pagination'
 import TagInput from '@/components/common/TagInput'
 import MainArea from '@/components/layout/MainArea'
 import { SITE_TITLE } from '@/config'
+import { clientAnimationTransition,
+	 clientScrollBehaviour } from '@/lib/clientAnimation'
 import { fetchPosts } from '@/lib/posts'
 import { postsKeys } from '@/lib/queryKeys'
 import {
@@ -24,6 +26,7 @@ import {
     LIST_LIMIT_OPTIONS,
     setClientListSettings,
 } from '@/lib/settings'
+import { useClientBehaviourSettings } from '@/lib/useClientBehaviourSettings'
 import { useKeyboardShortcuts } from '@/lib/useKeyboardShortcuts'
 import { dateString, inputClass, originalCreatedAtString } from '@/lib/utils'
 
@@ -67,6 +70,13 @@ const parseOrder = (value: string | null): FetchPostsOrder | null => {
 
 
 const PostSearchPage: FC = () => {
+  const behaviourSettings = useClientBehaviourSettings ()
+  const animationMode = behaviourSettings.animation ?? 'normal'
+  const thumbnailTransition = clientAnimationTransition (
+      animationMode,
+      { normal: { type: 'spring', stiffness: 500, damping: 40, mass: .5 },
+	reduced: { duration: .08, ease: 'linear' as const } },
+  )
   const location = useLocation ()
 
   const navigate = useNavigate ()
@@ -141,9 +151,11 @@ const PostSearchPage: FC = () => {
     setUpdatedFrom (qUpdatedFrom)
     setUpdatedTo (qUpdatedTo)
 
-    document.querySelector ('table')?.scrollIntoView ({ behavior: 'smooth' })
-  }, [location.search, qCreatedFrom, qCreatedTo, qMatch, qOriginalCreatedFrom,
-      qOriginalCreatedTo, qTags, qTitle, qUpdatedFrom, qUpdatedTo, qURL])
+    document.querySelector ('table')?.scrollIntoView ({
+	behavior: clientScrollBehaviour (animationMode) })
+  }, [animationMode, location.search, qCreatedFrom, qCreatedTo, qMatch,
+      qOriginalCreatedFrom, qOriginalCreatedTo, qTags, qTitle, qUpdatedFrom,
+      qUpdatedTo, qURL])
 
   const search = async () => {
     const qs = new URLSearchParams ()
@@ -400,11 +412,10 @@ const PostSearchPage: FC = () => {
 			  <td className="p-2">
 			    <PrefetchLink to={`/posts/${ row.id }`} title={row.title || undefined}>
 			      <motion.div
-				  layoutId={`page-${ row.id }`}
-				  transition={{ type: 'spring',
-						stiffness: 500,
-						damping: 40,
-						mass: .5 }}>
+				  layoutId={animationMode === 'off'
+				      ? undefined
+				      : `page-${ row.id }`}
+				  transition={thumbnailTransition}>
 				<img src={row.thumbnail || row.thumbnailBase || undefined}
 				     alt={row.title || row.url}
 				     title={row.title || row.url || undefined}

frontend/src/pages/tags/NicoTagListPage.test.tsx

@@ -6,6 +6,7 @@ import { dateString } from '@/lib/utils'
 import { buildTag, buildUser } from '@/test/factories'
 import { renderWithProviders } from '@/test/render'
 
+import type { ReactNode } from 'react'
 import type { NicoTag } from '@/types'
 
 const api = vi.hoisted (() => ({
@@ -27,6 +28,7 @@ const scrollIntoView = vi.fn ()
 vi.mock ('@/lib/api', () => api)
 vi.mock ('@/components/ui/use-toast', () => toastApi)
 vi.mock ('@/components/dialogues/DialogueProvider', () => ({
+  default: ({ children }: { children: ReactNode }) => <>{children}</>,
   useDialogue: () => dialogue,
 }))
 

frontend/src/pages/tags/NicoTagListPage.tsx

@@ -17,8 +17,10 @@ import { toast } from '@/components/ui/use-toast'
 import { SITE_TITLE } from '@/config'
 import { apiPut } from '@/lib/api'
 import { extractValidationError } from '@/lib/apiErrors'
+import { clientScrollBehaviour } from '@/lib/clientAnimation'
 import { tagsKeys } from '@/lib/queryKeys'
 import { fetchNicoTags } from '@/lib/tags'
+import { useClientBehaviourSettings } from '@/lib/useClientBehaviourSettings'
 import { cn, dateString, inputClass } from '@/lib/utils'
 import { canEditContent } from '@/lib/users'
 
@@ -38,6 +40,8 @@ const setIf = (qs: URLSearchParams, key: string, value: string) => {
 
 
 const NicoTagListPage: FC<Props> = ({ user }) => {
+  const behaviourSettings = useClientBehaviourSettings ()
+  const animationMode = behaviourSettings.animation ?? 'normal'
   const dialogue = useDialogue ()
   const location = useLocation ()
   const navigate = useNavigate ()
@@ -152,8 +156,9 @@ const NicoTagListPage: FC<Props> = ({ user }) => {
     setLinkStatus (qLinkStatus)
     setEditingId (null)
 
-    document.querySelector ('table')?.scrollIntoView ({ behavior: 'smooth' })
-  }, [location.search, qLinkedTag, qLinkStatus, qName])
+    document.querySelector ('table')?.scrollIntoView ({
+	behavior: clientScrollBehaviour (animationMode) })
+  }, [animationMode, location.search, qLinkedTag, qLinkStatus, qName])
 
   useEffect (() => {
     if (!(data))

frontend/src/pages/tags/TagHistoryPage.tsx

@@ -11,8 +11,10 @@ import { toast } from '@/components/ui/use-toast'
 import { SITE_TITLE } from '@/config'
 import { CATEGORY_NAMES } from '@/consts'
 import { apiPut } from '@/lib/api'
+import { clientScrollBehaviour } from '@/lib/clientAnimation'
 import { postsKeys, tagsKeys } from '@/lib/queryKeys'
 import { fetchTagChanges } from '@/lib/tags'
+import { useClientBehaviourSettings } from '@/lib/useClientBehaviourSettings'
 import { cn, dateString } from '@/lib/utils'
 
 import type { FC } from 'react'
@@ -43,6 +45,8 @@ const renderStateDiff = (diff: { current: string | null; prev: string | null })
 
 
 const TagHistoryPage: FC = () => {
+  const behaviourSettings = useClientBehaviourSettings ()
+  const animationMode = behaviourSettings.animation ?? 'normal'
   const location = useLocation ()
   const query = new URLSearchParams (location.search)
   const id = query.get ('id')
@@ -58,8 +62,9 @@ const TagHistoryPage: FC = () => {
   const qc = useQueryClient ()
 
   useEffect (() => {
-    document.querySelector ('table')?.scrollIntoView ({ behavior: 'smooth' })
-  }, [location.search])
+    document.querySelector ('table')?.scrollIntoView ({
+	behavior: clientScrollBehaviour (animationMode) })
+  }, [animationMode, location.search])
 
   return (
       <MainArea>

frontend/src/pages/tags/TagListPage.test.tsx

@@ -1,9 +1,10 @@
 import { fireEvent, screen, waitFor } from '@testing-library/react'
-import { describe, expect, it, vi } from 'vitest'
+import { beforeEach, describe, expect, it, vi } from 'vitest'
 
 import TagListPage from '@/pages/tags/TagListPage'
 import { buildTag } from '@/test/factories'
 import { renderWithProviders } from '@/test/render'
+import { CLIENT_SETTINGS_STORAGE_KEY } from '@/lib/settings'
 
 const tagsApi = vi.hoisted (() => ({
   fetchTags: vi.fn (),
@@ -12,6 +13,11 @@ const tagsApi = vi.hoisted (() => ({
 vi.mock ('@/lib/tags', () => tagsApi)
 
 describe ('TagListPage', () => {
+  beforeEach (() => {
+    localStorage.clear ()
+    vi.clearAllMocks ()
+  })
+
   it ('loads tags from URL filters and renders the results table', async () => {
     tagsApi.fetchTags.mockResolvedValueOnce ({
       tags: [buildTag ({
@@ -38,6 +44,8 @@ describe ('TagListPage', () => {
             name:         '虹',
             category:     'character',
             page:         3,
+            limit:        20,
+            order:        'post_count:desc',
             postCountGTE: 5,
             deprecated:   true,
           }),
@@ -48,7 +56,7 @@ describe ('TagListPage', () => {
         '/tags/7',
     )
     expect (screen.getAllByText ('キャラクター').length).toBeGreaterThan (0)
-    expect (screen.getAllByRole ('combobox')[1]).toHaveValue ('1')
+    expect (screen.getAllByRole ('combobox')[2]).toHaveValue ('1')
     expect (screen.getAllByText ('廃止')).toHaveLength (2)
   })
 
@@ -58,7 +66,7 @@ describe ('TagListPage', () => {
     renderWithProviders (<TagListPage/>, { route: '/tags' })
 
     fireEvent.change (screen.getByRole ('textbox'), { target: { value: '虹夏' } })
-    fireEvent.change (screen.getAllByRole ('combobox')[0], {
+    fireEvent.change (screen.getAllByRole ('combobox')[1], {
       target: { value: 'character' },
     })
     fireEvent.submit (screen.getByRole ('button', { name: '検索' }).closest ('form')!)
@@ -82,4 +90,41 @@ describe ('TagListPage', () => {
 
     expect (await screen.findByText ('結果ないよ（笑）')).toBeInTheDocument ()
   })
+
+  it ('uses URL limit before localStorage and preserves the query order', async () => {
+    localStorage.setItem (
+        CLIENT_SETTINGS_STORAGE_KEY,
+        JSON.stringify ({ lists: { tagList: { limit: 100, order: 'name:asc' } } }))
+    tagsApi.fetchTags.mockResolvedValueOnce ({ tags: [], count: 0 })
+
+    renderWithProviders (
+        <TagListPage/>,
+        { route: '/tags?limit=50&order=updated_at%3Adesc' },
+    )
+
+    await waitFor (() => {
+      expect (tagsApi.fetchTags).toHaveBeenCalledWith (
+          expect.objectContaining ({ limit: 50, order: 'updated_at:desc' }),
+      )
+    })
+    expect (JSON.parse (localStorage.getItem (CLIENT_SETTINGS_STORAGE_KEY) ?? '{}'))
+        .toMatchObject ({ lists: { tagList: { limit: 50, order: 'updated_at:desc' } } })
+  })
+
+  it ('keeps the compact limit control outside the search form and resets page on change', async () => {
+    tagsApi.fetchTags.mockResolvedValue ({ tags: [], count: 0 })
+
+    renderWithProviders (<TagListPage/>, { route: '/tags?page=4' })
+
+    const limitSelect = await screen.findByLabelText ('件数')
+    expect (limitSelect.closest ('form')).toBeNull ()
+
+    fireEvent.change (limitSelect, { target: { value: '100' } })
+
+    await waitFor (() => {
+      expect (tagsApi.fetchTags).toHaveBeenLastCalledWith (
+          expect.objectContaining ({ page: 1, limit: 100 }),
+      )
+    })
+  })
 })

frontend/src/pages/tags/TagListPage.tsx

@@ -13,6 +13,7 @@ import Pagination from '@/components/common/Pagination'
 import MainArea from '@/components/layout/MainArea'
 import { SITE_TITLE } from '@/config'
 import { CATEGORIES, CATEGORY_NAMES } from '@/consts'
+import { clientScrollBehaviour } from '@/lib/clientAnimation'
 import { tagsKeys } from '@/lib/queryKeys'
 import {
     DEFAULT_POST_LIST_LIMIT,
@@ -22,6 +23,7 @@ import {
     LIST_LIMIT_OPTIONS,
     setClientListSettings,
 } from '@/lib/settings'
+import { useClientBehaviourSettings } from '@/lib/useClientBehaviourSettings'
 import { useKeyboardShortcuts } from '@/lib/useKeyboardShortcuts'
 import { fetchTags } from '@/lib/tags'
 import { dateString, inputClass } from '@/lib/utils'
@@ -71,6 +73,8 @@ const parseOrder = (value: string | null): FetchTagsOrder | null => {
 
 
 const TagListPage: FC = () => {
+  const behaviourSettings = useClientBehaviourSettings ()
+  const animationMode = behaviourSettings.animation ?? 'normal'
   const location = useLocation ()
 
   const navigate = useNavigate ()
@@ -145,9 +149,11 @@ const TagListPage: FC = () => {
     setUpdatedTo (qUpdatedTo)
     setDeprecated (qDeprecated)
 
-    document.querySelector ('table')?.scrollIntoView ({ behavior: 'smooth' })
-  }, [location.search, qCategory, qCreatedFrom, qCreatedTo, qName, qPostCountGTE,
-      qPostCountLTE, qUpdatedFrom, qUpdatedTo, qDeprecated])
+    document.querySelector ('table')?.scrollIntoView ({
+	behavior: clientScrollBehaviour (animationMode) })
+  }, [animationMode, location.search, qCategory, qCreatedFrom, qCreatedTo,
+      qName, qPostCountGTE, qPostCountLTE, qUpdatedFrom, qUpdatedTo,
+      qDeprecated])
 
   const handleSearch = (e: FormEvent) => {
     e.preventDefault ()

frontend/src/pages/theatres/TheatreDetailPage.test.tsx

@@ -41,6 +41,7 @@ const postEmbed = vi.hoisted (() => ({
 vi.mock ('@/lib/api', () => api)
 vi.mock ('@/lib/posts', () => postsApi)
 vi.mock ('@/components/dialogues/DialogueProvider', () => ({
+  default: ({ children }: { children: ReactNode }) => <>{children}</>,
   useDialogue: () => dialogue,
 }))
 vi.mock ('@/components/PostEmbed', () => ({

frontend/src/pages/theatres/TheatreDetailPage.tsx

@@ -15,6 +15,8 @@ import { Button } from '@/components/ui/button'
 import { SITE_TITLE } from '@/config'
 import { CATEGORIES, CATEGORY_NAMES } from '@/consts'
 import { apiDelete, apiGet, apiPatch, apiPost, apiPut, isApiError } from '@/lib/api'
+import { clientAnimationTransition,
+	 clientScrollBehaviour } from '@/lib/clientAnimation'
 import { fetchPost } from '@/lib/posts'
 import {
   getClientTheatreLayoutMode,
@@ -22,6 +24,7 @@ import {
   setClientTheatreLayoutMode,
   setClientTheatreTagFlow,
 } from '@/lib/settings'
+import { useClientBehaviourSettings } from '@/lib/useClientBehaviourSettings'
 import { canEditContent } from '@/lib/users'
 import { cn, dateString, inputClass } from '@/lib/utils'
 import { useValidationErrors } from '@/lib/useValidationErrors'
@@ -57,8 +60,6 @@ const INITIAL_THEATRE_INFO: TheatreInfo =
 const INITIAL_WEIGHTS: TheatrePostSelectionWeights =
     { tagPenalties: [], lightestPosts: [], heaviestPosts: [] }
 
-const LAYOUT_STORAGE_KEY = 'theatre-layout-mode'
-const TAG_FLOW_STORAGE_KEY = 'theatre-tag-flow'
 const MIN_MAIN_WIDTH = 360
 const SIDEBAR_GAP_WIDTH = 16
 
@@ -214,6 +215,12 @@ type Props = { user: User | null }
 
 
 const TheatreDetailPage: FC<Props> = ({ user }: Props) => {
+  const behaviourSettings = useClientBehaviourSettings ()
+  const animationMode = behaviourSettings.animation ?? 'normal'
+  const layoutTransition = clientAnimationTransition (
+      animationMode,
+      { normal: { duration: .2, ease: 'easeOut' as const } },
+  )
   const { id } = useParams ()
   const dialogue = useDialogue ()
 
@@ -620,7 +627,9 @@ const TheatreDetailPage: FC<Props> = ({ user }: Props) => {
       clearValidationErrors ()
       await apiPost (`/theatres/${ id }/comments`, { content })
       setContent ('')
-      commentsRef.current?.scrollTo ({ top: 0, behavior: 'smooth' })
+      commentsRef.current?.scrollTo ({
+	  top: 0,
+	  behavior: clientScrollBehaviour (animationMode) })
     }
     catch (error)
     {
@@ -837,8 +846,8 @@ const TheatreDetailPage: FC<Props> = ({ user }: Props) => {
 
   return (
       <motion.div
-	  layout="position"
-	  transition={{ layout: { duration: .2, ease: 'easeOut' } }}
+	  layout={animationMode === 'off' ? false : 'position'}
+	  transition={{ layout: layoutTransition }}
 	  className="min-h-0 flex-1 overflow-y-auto bg-zinc-50 text-zinc-950
 		     md:overflow-hidden dark:bg-zinc-950 dark:text-zinc-50">
 	<Helmet>
@@ -862,7 +871,7 @@ const TheatreDetailPage: FC<Props> = ({ user }: Props) => {
 	      </SidebarComponent>)}
 
 	  <motion.main
-	      layout="position"
+	      layout={animationMode === 'off' ? false : 'position'}
 	      className="order-1 min-w-0 flex-1 space-y-4 md:order-none
 			 md:min-w-[360px] md:overflow-y-auto">
 	    <div className="space-y-4">

frontend/src/pages/users/SettingPage.test.tsx

@@ -6,6 +6,7 @@ import { buildUser } from '@/test/factories'
 import { renderWithProviders } from '@/test/render'
 
 const api = vi.hoisted (() => ({
+  apiGet:     vi.fn (),
   apiPut:     vi.fn (),
   isApiError: vi.fn (),
 }))
@@ -27,12 +28,23 @@ describe ('SettingPage', () => {
   beforeEach (() => {
     vi.clearAllMocks ()
     api.isApiError.mockReturnValue (false)
+    api.apiGet.mockImplementation ((path: string) => {
+      if (path === '/users/settings')
+	return Promise.resolve ({
+	    theme: 'system',
+	    auto_fetch_title: 'manual',
+	    auto_fetch_thumbnail: 'manual',
+	    wiki_editor_mode: 'split' })
+      if (path === '/users/theme_slots')
+	return Promise.resolve ([])
+      return Promise.resolve ({})
+    })
   })
 
   it ('shows loading when user is absent', () => {
     renderWithProviders (<SettingPage user={null} setUser={vi.fn ()}/>)
 
-    expect (screen.getByText ('Loading...')).toBeInTheDocument ()
+    expect (screen.getAllByText ('Loading...').length).toBeGreaterThan (0)
   })
 
   it ('updates the current user name', async () => {
@@ -42,8 +54,9 @@ describe ('SettingPage', () => {
 
     renderWithProviders (<SettingPage user={user} setUser={setUser}/>)
 
-    fireEvent.change (screen.getByRole ('textbox'), { target: { value: 'new' } })
-    fireEvent.click (screen.getByRole ('button', { name: '更新' }))
+    const nameInput = (await screen.findAllByRole ('textbox'))[0]
+    fireEvent.change (nameInput, { target: { value: 'new' } })
+    fireEvent.click (screen.getAllByRole ('button', { name: '表示名を更新' })[0])
 
     await waitFor (() => {
       expect (api.apiPut).toHaveBeenCalledWith (
@@ -55,7 +68,7 @@ describe ('SettingPage', () => {
     const formData = api.apiPut.mock.calls[0]?.[1] as FormData
     expect (formData.get ('name')).toBe ('new')
     expect (setUser).toHaveBeenCalled ()
-    expect (toastApi.toast).toHaveBeenCalledWith ({ title: '設定を更新しました．' })
+    expect (toastApi.toast).toHaveBeenCalledWith ({ title: '表示名を更新しました．' })
   })
 
   it ('shows validation errors returned for the name field', async () => {
@@ -75,10 +88,11 @@ describe ('SettingPage', () => {
 
     renderWithProviders (<SettingPage user={user} setUser={vi.fn ()}/>)
 
-    fireEvent.change (screen.getByRole ('textbox'), { target: { value: '' } })
-    fireEvent.click (screen.getByRole ('button', { name: '更新' }))
+    const nameInput = (await screen.findAllByRole ('textbox'))[0]
+    fireEvent.change (nameInput, { target: { value: '' } })
+    fireEvent.click (screen.getAllByRole ('button', { name: '表示名を更新' })[0])
 
-    expect (await screen.findByText ('名前は必須です．')).toBeInTheDocument ()
-    expect (screen.getByRole ('textbox')).toHaveAttribute ('aria-invalid', 'true')
+    expect ((await screen.findAllByText ('名前は必須です．')).length).toBeGreaterThan (0)
+    expect (nameInput).toHaveAttribute ('aria-invalid', 'true')
   })
 })

frontend/src/test/render.tsx

@@ -3,6 +3,10 @@ import { render } from '@testing-library/react'
 import { HelmetProvider } from 'react-helmet-async'
 import { MemoryRouter } from 'react-router-dom'
 
+import DialogueProvider from '@/components/dialogues/DialogueProvider'
+import { KeyboardShortcutsProvider } from '@/lib/useKeyboardShortcuts'
+import { UnsavedChangesGuardProvider } from '@/lib/useUnsavedChangesGuard'
+
 import type { ReactElement, ReactNode } from 'react'
 
 type Options = {
@@ -15,21 +19,25 @@ export const renderWithProviders = (
 ) => {
   const queryClient = new QueryClient ({
     defaultOptions: {
-      queries: { retry: false },
-    },
+      queries: { retry: false } },
   })
 
   const Wrapper = ({ children }: { children: ReactNode }) => (
       <QueryClientProvider client={queryClient}>
         <HelmetProvider>
           <MemoryRouter initialEntries={[options.route ?? '/']}>
-            {children}
+            <DialogueProvider>
+              <UnsavedChangesGuardProvider>
+                <KeyboardShortcutsProvider>
+                  {children}
+                </KeyboardShortcutsProvider>
+              </UnsavedChangesGuardProvider>
+            </DialogueProvider>
           </MemoryRouter>
         </HelmetProvider>
       </QueryClientProvider>)
 
   return {
     queryClient,
-    ...render (ui, { wrapper: Wrapper }),
-  }
+    ...render (ui, { wrapper: Wrapper }) }
 }

frontend/src/test/setup.ts

@@ -20,3 +20,10 @@ window.requestAnimationFrame = callback => {
   callback (0)
   return 0
 }
+
+Object.defineProperty (window, 'matchMedia', {
+    configurable: true,
+    value: vi.fn ().mockImplementation (() => ({
+	addEventListener: vi.fn (),
+	removeEventListener: vi.fn (),
+	matches: false })) })