feat: Establish core application layout, global styles, and theme mode management.

Frontend-Learner/assets/css/main.css

@@ -1113,3 +1113,33 @@ ul {
   color: var(--text-secondary);
   margin-bottom: 24px;
 }
+/* =========================
+   Discovery page: Quasar dark-mode overrides (scoped)
+   ไม่กระทบหน้าอื่น เพราะล็อคด้วย .discovery-page
+========================= */
+
+/* Dark mode: input background + border */
+html.dark .discovery-page .input-dark-override .q-field__control {
+  background-color: #0f172a !important; /* slate-900 */
+  border-color: rgba(255, 255, 255, 0.10) !important;
+}
+
+/* Dark mode: input text + icons */
+html.dark .discovery-page .input-dark-override .q-field__native,
+html.dark .discovery-page .input-dark-override .q-field__input,
+html.dark .discovery-page .input-dark-override .q-field__prefix,
+html.dark .discovery-page .input-dark-override .q-field__suffix,
+html.dark .discovery-page .input-dark-override .q-select__dropdown-icon,
+html.dark .discovery-page .input-dark-override .q-field__append .q-icon {
+  color: #ffffff !important;
+}
+
+/* Dark mode: placeholder */
+html.dark .discovery-page .input-dark-override .q-placeholder {
+  color: #94a3b8 !important; /* slate-400 */
+}
+
+/* Dark mode: category label ให้ชัดขึ้น (แก้กรณี class ไม่ติด) */
+html.dark .discovery-page .category-item .q-item__label {
+  color: #e2e8f0 !important; /* slate-200 */
+}

Frontend-Learner/components/user/UserMenu.vue

@@ -12,36 +12,13 @@ const { currentUser, logout } = useAuth()
 const { t } = useI18n()
 const $q = useQuasar()
 
-const isDarkMode = ref(false)
+// Use centralized theme management
+const { isDark, set } = useThemeMode()
+
 const isHydrated = ref(false)
 
-const applyTheme = (value: boolean) => {
-  // Tailwind dark mode
-  document.documentElement.classList.toggle('dark', value)
-
-  // Quasar dark mode
-  $q.dark.set(value)
-
-  // persist
-  localStorage.setItem('theme', value ? 'dark' : 'light')
-}
-
-const toggleDarkMode = (val: boolean) => {
-  isDarkMode.value = val
-  applyTheme(val)
-}
-
-// Sync Dark Mode state on mount
 onMounted(() => {
   isHydrated.value = true
-  const savedTheme = localStorage.getItem('theme')
-  const preferredDark = window.matchMedia?.('(prefers-color-scheme: dark)')?.matches ?? false
-
-  isDarkMode.value = savedTheme
-    ? savedTheme === 'dark'
-    : preferredDark
-
-  applyTheme(isDarkMode.value)
 })
 
 // User Initials
@@ -88,19 +65,19 @@ const handleLogout = async () => {
             class="hover:bg-slate-100 dark:hover:bg-white/10 transition-colors"
           >
             <q-item-section>
-              <q-item-label class="font-bold text-sm">{{ item.label }}</q-item-label>
+              <q-item-label class="font-bold text-sm text-slate-800 dark:text-white">{{ item.label }}</q-item-label>
             </q-item-section>
           </q-item>
 
           <q-item class="hover:bg-slate-100 dark:hover:bg-white/10 transition-colors">
             <q-item-section>
-              <q-item-label class="font-bold text-sm">{{ $t('userMenu.darkMode') }}</q-item-label>
+              <q-item-label class="font-bold text-sm text-slate-800 dark:text-white">{{ $t('userMenu.darkMode') }}</q-item-label>
             </q-item-section>
             <q-item-section side>
               <q-toggle
                 v-if="isHydrated"
-                :model-value="isDarkMode"
-                @update:model-value="toggleDarkMode"
+                :model-value="isDark"
+                @update:model-value="set"
                 color="blue"
                 keep-color
               />

Frontend-Learner/composables/useThemeMode.ts

@@ -0,0 +1,39 @@
+import { useQuasar } from 'quasar'
+
+export const useThemeMode = () => {
+  const $q = useQuasar()
+
+  // deterministic on SSR: default = light
+  const isDark = useState<boolean>('theme:isDark', () => false)
+
+  const applyTheme = (value: boolean) => {
+    if (!process.client) return
+    document.documentElement.classList.toggle('dark', value)
+    $q.dark.set(value)
+    localStorage.setItem('theme', value ? 'dark' : 'light')
+  }
+
+  const initTheme = () => {
+    if (!process.client) return
+    const saved = localStorage.getItem('theme') // 'dark' | 'light' | null
+    const prefersDark = window.matchMedia?.('(prefers-color-scheme: dark)')?.matches ?? false
+
+    const value = saved ? saved === 'dark' : prefersDark
+    isDark.value = value
+    applyTheme(value)
+  }
+
+  onMounted(initTheme)
+
+  watch(isDark, (v) => applyTheme(v))
+
+  const toggle = () => {
+    isDark.value = !isDark.value
+  }
+
+  const set = (v: boolean) => {
+    isDark.value = v
+  }
+
+  return { isDark, toggle, set }
+}

Frontend-Learner/layouts/default.vue

@@ -10,6 +10,9 @@ const leftDrawerOpen = ref(false)
 const toggleLeftDrawer = () => {
   leftDrawerOpen.value = !leftDrawerOpen.value
 }
+
+// Initialize global theme management
+useThemeMode()
 </script>
 
 <template>