#34

frontend/src/lib/settings.ts

@@ -212,6 +212,15 @@ const LEGACY_GEKANATOR_BACKGROUND_MOTION_STORAGE_KEY =
 const LEGACY_MIGRATED_THEME_ID = 'custom:legacy-migrated'
 
 
+const createCustomThemeId = (): `custom:${ string }` => {
+  const randomPart =
+      globalThis.crypto?.randomUUID?.()
+      ?? `${ Date.now ().toString (36) }-${ Math.random ().toString (36).slice (2) }`
+
+  return `custom:${ randomPart }`
+}
+
+
 export const fetchUserSettings = async (): Promise<UserSettings> => {
   const raw = await apiGet<{
       theme:               UserSettings['theme']
@@ -567,7 +576,7 @@ export const createCustomThemeFromBase = (
     baseTheme:   BuiltinThemeId,
     tokens?:     ThemeTokens,
 ): CustomClientTheme => {
-  const id = `custom:${ crypto.randomUUID () }` as ThemeId
+  const id = createCustomThemeId ()
   return {
       id,
       name: themeCopyName (baseTheme),