Styling updates, more robust dynamic/userpref light/dark switching. Sync with paskia-js.

frontend/auth/restricted/theme.js

@@ -1,11 +1,11 @@
 // Early theme for restricted app - first URL param wins, then localStorage
-import { themeColors, applyTheme, getCachedTheme } from '@/utils/theme.js'
+import { applyTheme, getCachedTheme } from '@/utils/theme.js'
 
 function getTheme() {
   const params = new URLSearchParams(location.hash.slice(1))
   return params.get('theme') || getCachedTheme() || ''
 }
 
-// Use .surface selector to preserve transparent background
-applyTheme(getTheme(), '.surface')
-addEventListener('hashchange', () => applyTheme(getTheme(), '.surface'))
+// Apply theme class to document root
+applyTheme(getTheme())
+addEventListener('hashchange', () => applyTheme(getTheme()))