feat:更新主题色兼容

lib/widgets/todo_form.dart

@@ -67,7 +67,11 @@ class _TodoFormState extends State<TodoForm> {
         label: RichText(
           text: TextSpan(
             text: '标题',
-            style: TextStyle(color: Colors.grey.shade700, fontSize: 16),
+            style: TextStyle(
+              color: Colors.grey,
+              fontSize: 16,
+              fontFamily: 'CustomFont',
+            ),
             children: const [
               TextSpan(
                 text: '*',
@@ -127,6 +131,7 @@ class _TodoFormState extends State<TodoForm> {
       },
       decoration: InputDecoration(
         labelText: '内容',
+        labelStyle: TextStyle(color: Colors.grey),
         hintText: '请输入待办事项内容...',
         hintStyle: TextStyle(color: Colors.grey),
         counterText: '',
@@ -188,11 +193,8 @@ class _TodoFormState extends State<TodoForm> {
         labelText:
             provider.formItem.dueDate == null
                 ? '选择截止日期'
-                : '截止: ${DateFormat('yyyy-MM-dd').format(provider.formItem.dueDate!)}',
-        labelStyle: TextStyle(
-          color:
-              provider.formItem.dueDate == null ? Colors.grey : Colors.black87,
-        ),
+                : '截止日期: ${DateFormat('yyyy-MM-dd').format(provider.formItem.dueDate!)}',
+        labelStyle: TextStyle(color: Colors.grey),
         prefixIcon: Icon(Icons.calendar_month, color: Colors.purple),
         border: OutlineInputBorder(
           borderRadius: BorderRadius.circular(12),
@@ -252,14 +254,9 @@ class _TodoFormState extends State<TodoForm> {
       decoration: InputDecoration(
         labelText:
             provider.formItem.scheduledTime == null
-                ? '选择提醒日期'
-                : '提醒: ${DateFormat('yyyy-MM-dd HH:mm:ss').format(provider.formItem.scheduledTime!)}',
-        labelStyle: TextStyle(
-          color:
-              provider.formItem.scheduledTime == null
-                  ? Colors.grey
-                  : Colors.black87,
-        ),
+                ? '选择提醒时间'
+                : '提醒时间: ${DateFormat('yyyy-MM-dd HH:mm:ss').format(provider.formItem.scheduledTime!)}',
+        labelStyle: TextStyle(color: Colors.grey),
         prefixIcon: Icon(Icons.calendar_month, color: Colors.purple),
         border: OutlineInputBorder(
           borderRadius: BorderRadius.circular(12),