feat(ui) : add dark mode toggle and remove inline dark: classes

- Add dark mode toggle button in top nav
- Add darkMode store with localStorage persistence
- Enable Tailwind class-based dark mode
- Import dark.css global overrides
- Remove inline dark: Tailwind classes (handled by global CSS)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/components/task/TaskCard.vue

@@ -1,6 +1,6 @@
 <template>
     <div
-        class="cursor-pointer rounded-lg border border-neutral-200 bg-white p-3 shadow-sm transition hover:shadow-md dark:border-dark-border dark:bg-dark-card"
+        class="cursor-pointer rounded-lg border border-neutral-200 bg-white p-3 shadow-sm transition hover:shadow-md"
         draggable="true"
         @dragstart="onDragStart"
         @dragend="onDragEnd"
@@ -27,7 +27,7 @@
                         :title="$t('clientTicket.linkedTooltip', { number: 'CT-' + String(task.clientTicket.number).padStart(3, '0') })"
                     />
                 </div>
-                <h4 class="text-sm font-semibold text-neutral-900 dark:text-neutral-100">{{ task.title }}</h4>
+                <h4 class="text-sm font-semibold text-neutral-900">{{ task.title }}</h4>
             </div>
             <button
                 class="shrink-0 transition-colors"
@@ -85,7 +85,7 @@
             />
             <span
                 v-else
-                class="ml-auto flex h-5 w-5 items-center justify-center rounded-full bg-neutral-200 text-neutral-400 dark:bg-dark-hover dark:text-neutral-400"
+                class="ml-auto flex h-5 w-5 items-center justify-center rounded-full bg-neutral-200 text-neutral-400"
             >
                 <Icon name="mdi:account-outline" size="14" />
             </span>

frontend/components/task/TaskListItem.vue

@@ -1,6 +1,6 @@
 <template>
     <div
-        class="flex cursor-pointer items-stretch gap-3 rounded-[10px] bg-white px-3 py-2.5 transition-colors hover:shadow-sm sm:px-4 dark:bg-dark-card"
+        class="flex cursor-pointer items-stretch gap-3 rounded-[10px] bg-white px-3 py-2.5 transition-colors hover:shadow-sm sm:px-4"
         :class="selected ? 'ring-2 ring-primary-500' : ''"
         @click="emit('click')"
     >
@@ -30,7 +30,7 @@
                 />
             </div>
             <!-- Row 2: title -->
-            <h4 class="mt-1 text-sm font-semibold text-neutral-900 dark:text-neutral-100">{{ task.title }}</h4>
+            <h4 class="mt-1 text-sm font-semibold text-neutral-900">{{ task.title }}</h4>
             <!-- Row 3: tags + status + deadline/calendar/recurrence -->
             <div class="mt-2 flex flex-wrap items-center gap-1.5">
                 <span
@@ -92,7 +92,7 @@
             />
             <span
                 v-else
-                class="flex h-5 w-5 items-center justify-center rounded-full bg-neutral-200 text-neutral-400 dark:bg-dark-hover"
+                class="flex h-5 w-5 items-center justify-center rounded-full bg-neutral-200 text-neutral-400"
             >
                 <Icon name="mdi:account-outline" size="14" />
             </span>

frontend/components/ui/AppTopNav.vue

@@ -19,6 +19,14 @@
         </button>
       </div>
       <div class="ml-auto flex items-center gap-4 text-xl text-white sm:gap-8">
+        <button
+          type="button"
+          class="rounded-md p-1.5 text-white/70 transition-colors hover:bg-primary-600 hover:text-white"
+          :title="ui.darkMode ? 'Mode clair' : 'Mode sombre'"
+          @click="ui.toggleDarkMode()"
+        >
+          <Icon :name="ui.darkMode ? 'mdi:weather-sunny' : 'mdi:weather-night'" size="22" />
+        </button>
         <NotificationBell />
         <div class="group relative flex gap-2 sm:gap-4">
           <UserAvatar v-if="user" :user="user" size="md" class="cursor-pointer" />

frontend/nuxt.config.ts

@@ -2,6 +2,7 @@ export default defineNuxtConfig({
     compatibilityDate: '2025-07-15',
     devtools: {enabled: false},
     ssr: false,
+    css: ['~/assets/css/dark.css'],
     app: {
         baseURL: process.env.NODE_ENV === 'production'
             ? (process.env.NUXT_PUBLIC_APP_BASE || '/')

frontend/pages/my-tasks.vue

@@ -320,7 +320,7 @@ onMounted(async () => {
 <template>
     <div class="min-w-0">
         <!-- Header + Filters -->
-        <div class="sticky top-8 z-20 bg-white pb-4 sm:top-12 dark:bg-dark-base">
+        <div class="sticky top-8 z-20 bg-white pb-4 sm:top-12">
             <div class="flex items-center justify-between gap-3">
                 <h1 class="text-xl font-bold text-primary-500 sm:text-2xl">{{ $t('myTasks.title') }}</h1>
                 <div class="flex items-center gap-2">
@@ -420,7 +420,7 @@ onMounted(async () => {
                     v-for="status in sortedStatuses"
                     :key="status.id"
                     class="flex min-w-36 flex-1 flex-col rounded-lg transition-colors"
-                    :class="dragOverStatusId === status.id ? 'bg-neutral-200 dark:bg-dark-hover' : 'bg-neutral-50 dark:bg-dark-surface/50'"
+                    :class="dragOverStatusId === status.id ? 'bg-neutral-200' : 'bg-neutral-50'"
                     @dragover.prevent
                     @dragenter.prevent="onDragEnter(status.id)"
                     @dragleave="onDragLeave"
@@ -455,13 +455,13 @@ onMounted(async () => {
             <!-- Backlog below kanban -->
             <div
                 class="mt-8 rounded-lg p-4 transition-colors"
-                :class="dragOverStatusId === 0 ? 'bg-neutral-200 dark:bg-dark-hover' : 'bg-neutral-50 dark:bg-dark-surface'"
+                :class="dragOverStatusId === 0 ? 'bg-neutral-200' : 'bg-neutral-50'"
                 @dragover.prevent
                 @dragenter.prevent="onDragEnter(0)"
                 @dragleave="onDragLeave"
                 @drop.prevent="onDropBacklog($event)"
             >
-                <h2 class="text-lg font-bold text-neutral-900 dark:text-neutral-100">{{ $t('myTasks.backlog') }} ({{ backlogTasks.length }})</h2>
+                <h2 class="text-lg font-bold text-neutral-900">{{ $t('myTasks.backlog') }} ({{ backlogTasks.length }})</h2>
                 <div class="mt-4 grid grid-cols-1 gap-3 sm:grid-cols-2 lg:grid-cols-3 xl:grid-cols-4">
                     <TaskCard
                         v-for="task in backlogTasks"
@@ -481,7 +481,7 @@ onMounted(async () => {
         </div>
 
         <!-- List View -->
-        <div v-if="viewMode === 'list'" class="mt-6 flex flex-col gap-2.5 rounded-[10px] bg-tertiary-500 p-2.5 dark:bg-dark-surface">
+        <div v-if="viewMode === 'list'" class="mt-6 flex flex-col gap-2.5 rounded-[10px] bg-tertiary-500 p-2.5">
             <TaskBulkActions
                 :selected-count="selectedTaskIds.size"
                 :total-count="tasks.length"

frontend/stores/ui.ts

@@ -1,12 +1,19 @@
 export const useUiStore = defineStore('ui', () => {
     const sidebarCollapsed = ref(false)
     const sidebarOpen = ref(false)
+    const darkMode = ref(false)
 
     if (import.meta.client) {
         const saved = localStorage.getItem('ui-sidebar-collapsed')
         if (saved !== null) {
             sidebarCollapsed.value = saved === 'true'
         }
+
+        const savedDark = localStorage.getItem('ui-dark-mode')
+        if (savedDark !== null) {
+            darkMode.value = savedDark === 'true'
+        }
+        applyDarkClass(darkMode.value)
     }
 
     watch(sidebarCollapsed, (val) => {
@@ -15,6 +22,25 @@ export const useUiStore = defineStore('ui', () => {
         }
     })
 
+    watch(darkMode, (val) => {
+        if (import.meta.client) {
+            localStorage.setItem('ui-dark-mode', String(val))
+            applyDarkClass(val)
+        }
+    })
+
+    function applyDarkClass(dark: boolean) {
+        if (dark) {
+            document.documentElement.classList.add('dark')
+        } else {
+            document.documentElement.classList.remove('dark')
+        }
+    }
+
+    function toggleDarkMode() {
+        darkMode.value = !darkMode.value
+    }
+
     function toggleSidebar() {
         sidebarCollapsed.value = !sidebarCollapsed.value
     }
@@ -27,5 +53,5 @@ export const useUiStore = defineStore('ui', () => {
         sidebarOpen.value = false
     }
 
-    return { sidebarCollapsed, sidebarOpen, toggleSidebar, openMobileSidebar, closeMobileSidebar }
+    return { sidebarCollapsed, sidebarOpen, darkMode, toggleSidebar, openMobileSidebar, closeMobileSidebar, toggleDarkMode }
 })

frontend/tailwind.config.ts

@@ -1,6 +1,7 @@
 import type {Config} from 'tailwindcss'
 
 export default <Partial<Config>>{
+    darkMode: 'class',
     theme: {
         extend: {
             fontFamily: {