feat:更新主题颜色布局

lib/pages/task_page.dart

@@ -123,13 +123,13 @@ class _TaskPageState extends State<TaskPage> {
   Widget build(BuildContext context) {
     return ScaffoldPage.withPadding(
       header: PageHeader(
-        title: const Text('待办任务'),
+        title: const Text('待办任务', style: TextStyle(color: Colors.white)),
         commandBar: CommandBar(
           mainAxisAlignment: MainAxisAlignment.end,
           primaryItems: [
             CommandBarButton(
-              icon: const Icon(FluentIcons.add),
-              label: const Text('添加任务'),
+              icon: const Icon(FluentIcons.add, color: Colors.white),
+              label: const Text('添加任务', style: TextStyle(color: Colors.white)),
               onPressed: _addTask,
             ),
           ],
@@ -155,7 +155,6 @@ class _TaskPageState extends State<TaskPage> {
     final activeCount = _tasks.length - completedCount;
 
     return Card(
-      backgroundColor: FluentTheme.of(context).accentColor.lighter,
       child: Padding(
         padding: const EdgeInsets.all(12.0),
         child: Row(
@@ -175,21 +174,16 @@ class _TaskPageState extends State<TaskPage> {
       children: [
         Text(
           value,
-          style: TextStyle(
-            fontSize: 24,
-            fontWeight: FontWeight.bold,
-            color: Colors.white,
-          ),
+          style: TextStyle(fontSize: 24, fontWeight: FontWeight.bold),
         ),
         const SizedBox(height: 4),
-        Text(label, style: TextStyle(color: Colors.white)),
+        Text(label),
       ],
     );
   }
 
   Widget _buildFilterWidget() {
     return Card(
-      borderColor: Colors.white,
       child: Padding(
         padding: const EdgeInsets.all(12.0),
         child: Row(