feat(flutter): 剧场页搜索与吸顶筛选精致化

lib/pages/discover/widgets/discover_search_field.dart

@@ -6,10 +6,11 @@ import '../../../core/theme/app_colors.dart';
 import '../../../l10n/app_localizations.dart';
 
 const double _searchHeight = 40;
-const double _searchRadius = 18;
+const double _searchRadius = 20;
+const Duration _focusTransition = Duration(milliseconds: 160);
 
-/// 剧场顶部整行搜索框。
-class DiscoverSearchField extends StatelessWidget {
+/// 剧场顶部整行搜索框：白底细边，聚焦时主题色描边与更深的阴影。
+class DiscoverSearchField extends StatefulWidget {
   const DiscoverSearchField({
     super.key,
     required this.controller,
@@ -25,32 +26,84 @@ class DiscoverSearchField extends StatelessWidget {
   final bool loading;
   final double horizontalPadding;
 
+  @override
+  State<DiscoverSearchField> createState() => _DiscoverSearchFieldState();
+}
+
+class _DiscoverSearchFieldState extends State<DiscoverSearchField> {
+  bool _focused = false;
+
+  @override
+  void initState() {
+    super.initState();
+    widget.focusNode.addListener(_onFocusChanged);
+  }
+
+  @override
+  void didUpdateWidget(covariant DiscoverSearchField oldWidget) {
+    super.didUpdateWidget(oldWidget);
+    if (oldWidget.focusNode != widget.focusNode) {
+      oldWidget.focusNode.removeListener(_onFocusChanged);
+      widget.focusNode.addListener(_onFocusChanged);
+      _focused = widget.focusNode.hasFocus;
+    }
+  }
+
+  @override
+  void dispose() {
+    widget.focusNode.removeListener(_onFocusChanged);
+    super.dispose();
+  }
+
+  void _onFocusChanged() {
+    final focused = widget.focusNode.hasFocus;
+    if (focused != _focused) setState(() => _focused = focused);
+  }
+
   @override
   Widget build(BuildContext context) {
     return Padding(
-      padding: EdgeInsets.symmetric(horizontal: horizontalPadding),
-      child: SizedBox(
+      padding: EdgeInsets.symmetric(horizontal: widget.horizontalPadding),
+      child: AnimatedContainer(
+        key: const Key('discover-search-shell'),
+        duration: _focusTransition,
+        curve: Curves.easeOut,
         height: _searchHeight,
+        decoration: BoxDecoration(
+          color: AppColors.card,
+          borderRadius: BorderRadius.circular(_searchRadius),
+          border: Border.all(
+            color: _focused ? AppColors.blue : AppColors.border,
+          ),
+          boxShadow: [
+            BoxShadow(
+              color: _focused
+                  ? AppColors.blue.withValues(alpha: 0.18)
+                  : Colors.black.withValues(alpha: 0.04),
+              blurRadius: _focused ? 10 : 4,
+              offset: const Offset(0, 2),
+            ),
+          ],
+        ),
         child: TextField(
           key: const Key('discover-search'),
-          controller: controller,
-          focusNode: focusNode,
-          onChanged: onChanged,
-          onTapOutside: (_) => focusNode.unfocus(),
+          controller: widget.controller,
+          focusNode: widget.focusNode,
+          onChanged: widget.onChanged,
+          onTapOutside: (_) => widget.focusNode.unfocus(),
           textInputAction: TextInputAction.search,
           style: const TextStyle(color: AppColors.onSurface, fontSize: 14),
           decoration: InputDecoration(
             isDense: true,
-            filled: true,
-            fillColor: AppColors.card,
+            filled: false,
             hintText: AppLocalizations.of(context)!.searchDiscover,
-            hintStyle: const TextStyle(color: AppColors.subtle, fontSize: 12),
+            hintStyle: const TextStyle(color: AppColors.subtle, fontSize: 13.5),
             prefixIcon: const Icon(
               Icons.search_rounded,
               color: AppColors.subtle,
               size: 17,
             ),
-            suffixIcon: loading
+            suffixIcon: widget.loading
                 ? const SizedBox.square(
                     dimension: 18,
                     child: Center(
@@ -63,14 +116,9 @@ class DiscoverSearchField extends StatelessWidget {
               minHeight: 0,
             ),
             contentPadding: const EdgeInsets.symmetric(horizontal: 12),
-            enabledBorder: OutlineInputBorder(
-              borderRadius: BorderRadius.circular(_searchRadius),
-              borderSide: BorderSide.none,
-            ),
-            focusedBorder: OutlineInputBorder(
-              borderRadius: BorderRadius.circular(_searchRadius),
-              borderSide: const BorderSide(color: AppColors.blue, width: 1),
-            ),
+            border: InputBorder.none,
+            enabledBorder: InputBorder.none,
+            focusedBorder: InputBorder.none,
           ),
         ),
       ),