style(nav): 对齐四 Tab 底栏布局规格

lib/core/theme/app_colors.dart

@@ -69,10 +69,9 @@ abstract final class AppColors {
   /// 底部导航底色。
   static const bar = ink;
 
-  /// 底部导航专用：纯黑背景、选中白、未选中灰与轻分割线。
+  /// 底部导航专用：纯黑背景、选中白与未选中灰。
   static const navBackground = Color(0xFF000000);
   static const navSelected = Color(0xFFFFFFFF);
-  static const navDivider = Color(0xFF1C1C1E);
 
   /// 卡片阴影（深色几乎不用阴影）。
   static const cardShadow = Color(0x00000000);
@@ -126,7 +125,7 @@ abstract final class AppColors {
   static const badgeBeige = raised;
 
   /// 导航未选中。
-  static const navUnselected = Color(0xFF8A8A8E);
+  static const navUnselected = Color(0xFF8E8E93);
 
   /// 播放器次要文字。
   static const playerMuted = Color(0xA3FFFFFF);

lib/core/theme/app_dimens.dart

@@ -37,6 +37,7 @@ abstract final class AppDimens {
   static const double previewSectionTitle = 14;
   static const double chipFont = 10;
   static const double navLabel = 11;
+  static const double navLabelGap = 4;
 
   static const double buttonHeight = 48;
   static const double primaryButtonHeight = 52;
@@ -47,8 +48,8 @@ abstract final class AppDimens {
   static const double tapTarget = 44;
   static const double contentHeaderHeight = 46;
 
-  static const double navHeight = 68;
-  static const double navIcon = 24;
+  static const double navHeight = 56;
+  static const double navIcon = 26;
   static const double progressHeight = 3;
   static const double progressRadius = 2;
   static const double progressLineHeight = 3;

lib/core/widgets/app_bottom_nav.dart

@@ -26,30 +26,17 @@ class AppBottomNavItem {
 
 /// 四槽底部导航：纯黑背景，白色选中态，灰色未选中态。
 class AppBottomNav extends StatelessWidget {
-  const AppBottomNav({
-    super.key,
-    required this.items,
-    this.backgroundColor = AppColors.navBackground,
-    this.barKey,
-    this.dark = false,
-  });
+  const AppBottomNav({super.key, required this.items, this.barKey});
 
   final List<AppBottomNavItem> items;
-  final Color backgroundColor;
   final Key? barKey;
-  final bool dark;
 
   @override
   Widget build(BuildContext context) {
     final bar = Container(
       key: barKey,
       height: AppDimens.navHeight,
-      decoration: BoxDecoration(
-        color: dark ? AppColors.navBackground : backgroundColor,
-        border: const Border(
-          top: BorderSide(color: AppColors.navDivider, width: 0.5),
-        ),
-      ),
+      color: AppColors.navBackground,
       child: Row(
         children: [
           for (final item in items)
@@ -99,7 +86,7 @@ class _NavDestination extends StatelessWidget {
                       : unselectedColor,
                 ),
               ),
-              const SizedBox(height: 3),
+              const SizedBox(height: AppDimens.navLabelGap),
               Text(
                 item.label,
                 maxLines: 1,

lib/core/widgets/app_root_tab.dart

@@ -3,6 +3,7 @@
 import 'package:flutter/material.dart';
 
 import '../../l10n/app_localizations.dart';
+import 'app_bottom_nav.dart';
 
 /// 客户端根导航的固定顺序。
 enum AppRootTab { home, recommend, following, mine }
@@ -36,3 +37,36 @@ extension AppRootTabUi on AppRootTab {
     AppRootTab.mine => l10n.myTab,
   };
 }
+
+/// 根导航唯一入口，确保四个主页面使用完全一致的底栏配置。
+class AppRootBottomNav extends StatelessWidget {
+  const AppRootBottomNav({
+    super.key,
+    required this.selected,
+    required this.onSelected,
+    this.barKey,
+  });
+
+  final AppRootTab selected;
+  final ValueChanged<AppRootTab> onSelected;
+  final Key? barKey;
+
+  @override
+  Widget build(BuildContext context) {
+    final l10n = AppLocalizations.of(context)!;
+    return AppBottomNav(
+      barKey: barKey,
+      items: [
+        for (final tab in AppRootTab.values)
+          AppBottomNavItem(
+            tabKey: tab.tabKey,
+            icon: tab.icon,
+            selectedIcon: tab.selectedIcon,
+            label: tab.label(l10n),
+            selected: tab == selected,
+            onTap: () => onSelected(tab),
+          ),
+      ],
+    );
+  }
+}

lib/pages/discover/discover_view.dart

@@ -17,7 +17,6 @@ import '../../core/formatting/error_text.dart';
 import '../../core/theme/app_colors.dart';
 import '../../core/theme/app_dimens.dart';
 import '../../core/theme/app_theme.dart';
-import '../../core/widgets/app_bottom_nav.dart';
 import '../../core/widgets/app_pull_to_refresh.dart';
 import '../../core/widgets/app_root_tab.dart';
 import '../../core/widgets/catalog_debug_info.dart';
@@ -160,7 +159,7 @@ class _DiscoverPageState extends State<DiscoverPage> {
               loading: logic.searchLoading,
             ),
             Expanded(child: _feed(l10n, categories)),
-            if (!embedded) _bottomNav(l10n),
+            if (!embedded) _bottomNav(),
           ],
         ),
       ),
@@ -612,20 +611,9 @@ class _DiscoverPageState extends State<DiscoverPage> {
     unawaited(playDramaFromCatalog(context, drama));
   }
 
-  Widget _bottomNav(AppLocalizations l10n) => AppBottomNav(
-    items: [
-      for (final tab in AppRootTab.values)
-        AppBottomNavItem(
-          tabKey: tab.tabKey,
-          icon: tab.icon,
-          selectedIcon: tab.selectedIcon,
-          label: tab.label(l10n),
-          selected: tab == AppRootTab.recommend,
-          onTap: tab == AppRootTab.recommend
-              ? () {}
-              : () => _act(_actionOf(tab)),
-        ),
-    ],
+  Widget _bottomNav() => AppRootBottomNav(
+    selected: AppRootTab.recommend,
+    onSelected: (tab) => _act(_actionOf(tab)),
   );
 
   DiscoverPageAction _actionOf(AppRootTab tab) => switch (tab) {

lib/pages/home/home_view.dart

@@ -16,7 +16,6 @@ import '../../core/data/services/category_controller.dart';
 import '../../core/platform/haptics.dart';
 import '../../core/theme/app_colors.dart';
 import '../../core/theme/app_theme.dart';
-import '../../core/widgets/app_bottom_nav.dart';
 import '../../core/widgets/app_root_tab.dart';
 import '../../core/widgets/catalog_debug_info.dart';
 import '../../core/widgets/catalog_endpoint_editor.dart';
@@ -262,7 +261,6 @@ class _HomeTabsState extends State<_HomeTabs> {
   }
 
   Widget _scaffold(BuildContext context) {
-    final l10n = AppLocalizations.of(context)!;
     final feed = logic.tab == 0;
     final content = PopScope(
       canPop: false,
@@ -275,7 +273,7 @@ class _HomeTabsState extends State<_HomeTabs> {
         backgroundColor: AppColors.transparent,
         resizeToAvoidBottomInset: false,
         body: _body(context),
-        bottomNavigationBar: logic.videoImmersive ? null : _nav(context, l10n),
+        bottomNavigationBar: logic.videoImmersive ? null : _nav(context),
       ),
     );
     return AnnotatedRegion<SystemUiOverlayStyle>(
@@ -451,31 +449,11 @@ class _HomeTabsState extends State<_HomeTabs> {
     );
   }
 
-  Widget _nav(BuildContext context, AppLocalizations l10n) {
-    return AppBottomNav(
+  Widget _nav(BuildContext context) {
+    return AppRootBottomNav(
       barKey: const Key('home-tabs-bar'),
-      dark: logic.tab == 0,
-      items: [
-        _navItem(context, l10n, AppRootTab.home),
-        _navItem(context, l10n, AppRootTab.recommend),
-        _navItem(context, l10n, AppRootTab.following),
-        _navItem(context, l10n, AppRootTab.mine),
-      ],
-    );
-  }
-
-  AppBottomNavItem _navItem(
-    BuildContext context,
-    AppLocalizations l10n,
-    AppRootTab tab,
-  ) {
-    return AppBottomNavItem(
-      tabKey: tab.tabKey,
-      icon: tab.icon,
-      selectedIcon: tab.selectedIcon,
-      label: tab.label(l10n),
-      selected: logic.tab == tab.index,
-      onTap: () => _selectTab(context, tab.index),
+      selected: AppRootTab.values[logic.tab],
+      onSelected: (tab) => _selectTab(context, tab.index),
     );
   }
 

lib/pages/mine/mine_view.dart

@@ -12,7 +12,6 @@ import '../../core/data/services/wallet_controller.dart';
 import '../../core/theme/app_colors.dart';
 import '../../core/theme/app_dimens.dart';
 import '../../core/theme/app_theme.dart';
-import '../../core/widgets/app_bottom_nav.dart';
 import '../../core/widgets/app_root_tab.dart';
 import '../../core/widgets/auth_gate.dart';
 import '../../core/widgets/plain_page_scaffold.dart';
@@ -87,7 +86,7 @@ class _MyPageState extends State<MyPage> {
         children: [
           _topBar(l10n),
           Expanded(child: _body(context, l10n)),
-          if (!embedded) _bottomNav(l10n),
+          if (!embedded) _bottomNav(),
         ],
       ),
     );
@@ -238,19 +237,10 @@ class _MyPageState extends State<MyPage> {
     _openProtected(RechargePage(onPurchased: () => unawaited(wallet.load())));
   }
 
-  Widget _bottomNav(AppLocalizations l10n) {
-    return AppBottomNav(
-      items: [
-        for (final tab in AppRootTab.values)
-          AppBottomNavItem(
-            tabKey: tab.tabKey,
-            icon: tab.icon,
-            selectedIcon: tab.selectedIcon,
-            label: tab.label(l10n),
-            selected: tab == AppRootTab.mine,
-            onTap: tab == AppRootTab.mine ? () {} : () => _act(_actionOf(tab)),
-          ),
-      ],
+  Widget _bottomNav() {
+    return AppRootBottomNav(
+      selected: AppRootTab.mine,
+      onSelected: (tab) => _act(_actionOf(tab)),
     );
   }