优化：UI调整

lib/design/pencil_theme.dart

@@ -7,6 +7,20 @@ abstract final class PencilTheme {
 
   static const Color homeTextPrimary = Colors.white;
   static const Color homeTabDivider = Color(0x66FFFFFF);
+
+  /// Home 积分数字（顶栏胶囊、Create Now 上方预估）共用投影。
+  static const List<Shadow> homeCreditsTextShadows = [
+    Shadow(
+      offset: Offset(0, 1),
+      blurRadius: 4,
+      color: Color(0x73000000),
+    ),
+    Shadow(
+      offset: Offset(0, 0),
+      blurRadius: 8,
+      color: Color(0x40000000),
+    ),
+  ];
   static const Color gemYellow = Color(0xFFFFD60A);
 
   /// 旧版 Create Now 磨砂底（当前 UI 已改用金渐变 [PencilCreateNowButton]；保留供参考）。
@@ -63,4 +77,10 @@ abstract final class PencilTheme {
 
   /// 设计宽度用于按比例缩放（可选）。
   static const double designWidth = 390;
+
+  /// [MainScreen] 使用 [Scaffold.extendBody] 时，M3 [NavigationBar] 浮在内容上方；
+  /// 内容区默认高度为 80（与 Flutter `navigation_bar.dart` 一致），外加系统底边安全区。
+  static double mainTabBottomChromeReserve(BuildContext context) {
+    return 80 + MediaQuery.paddingOf(context).bottom;
+  }
 }

lib/features/history/credit_record_tab.dart

@@ -8,7 +8,10 @@ import '../../design/pencil_theme.dart';
 
 /// WBRp4「Credit Record」内容区 — 对齐 `funymee_home.pen` [listCr]（ez9wP）。
 class CreditRecordTab extends StatefulWidget {
-  const CreditRecordTab({super.key});
+  const CreditRecordTab({super.key, this.extraBottomInset = 0});
+
+  /// [MainScreen] 底栏浮在内容上时，为列表底部追加的留白（与 [PencilTheme.mainTabBottomChromeReserve] 一致）。
+  final double extraBottomInset;
 
   @override
   State<CreditRecordTab> createState() => _CreditRecordTabState();
@@ -71,13 +74,19 @@ class _CreditRecordTabState extends State<CreditRecordTab> {
 
   @override
   Widget build(BuildContext context) {
+    final bottomPad = EdgeInsets.only(bottom: widget.extraBottomInset);
     if (_loading) {
-      return const Center(
+      return Padding(
+        padding: bottomPad,
+        child: const Center(
           child: CircularProgressIndicator(color: PencilTheme.underlineGold),
+        ),
       );
     }
     if (_error != null) {
-      return Center(
+      return Padding(
+        padding: bottomPad,
+        child: Center(
           child: Column(
             mainAxisSize: MainAxisSize.min,
             children: [
@@ -85,21 +94,30 @@ class _CreditRecordTabState extends State<CreditRecordTab> {
               TextButton(onPressed: _load, child: const Text('Retry')),
             ],
           ),
+        ),
       );
     }
     if (_records.isEmpty) {
-      return Center(
+      return Padding(
+        padding: bottomPad,
+        child: Center(
           child: Text(
             'No records.',
             style: GoogleFonts.inter(color: PencilTheme.inkSoft),
           ),
+        ),
       );
     }
     return RefreshIndicator(
       color: PencilTheme.underlineGold,
       onRefresh: _load,
       child: ListView.separated(
-        padding: const EdgeInsets.fromLTRB(16, 8, 16, 28),
+        padding: EdgeInsets.fromLTRB(
+          16,
+          8,
+          16,
+          28 + widget.extraBottomInset,
+        ),
         itemCount: _records.length,
         separatorBuilder: (_, _) => const SizedBox(height: 12),
         itemBuilder: (_, i) {

lib/features/history/history_screen.dart

@@ -150,7 +150,13 @@ class _HistoryScreenState extends State<HistoryScreen> {
                 ),
               ),
               Expanded(
-                child: _tab == 0 ? _myHistoryBody() : const CreditRecordTab(),
+                child: _tab == 0
+                    ? _myHistoryBody()
+                    : CreditRecordTab(
+                        extraBottomInset: widget.isRootTab
+                            ? PencilTheme.mainTabBottomChromeReserve(context)
+                            : 0,
+                      ),
               ),
             ],
           ),
@@ -196,12 +202,20 @@ class _HistoryScreenState extends State<HistoryScreen> {
     if (!widget.isTabSelected) {
       return const SizedBox.shrink();
     }
+    final shellBottom = widget.isRootTab
+        ? PencilTheme.mainTabBottomChromeReserve(context)
+        : 0.0;
     if (!AuthService.isLoginComplete.value) {
-      return const Center(child: CircularProgressIndicator());
+      return Padding(
+        padding: EdgeInsets.only(bottom: shellBottom),
+        child: const Center(child: CircularProgressIndicator()),
+      );
     }
     final uid = UserState.userId.value;
     if (uid == null || uid.isEmpty) {
-      return Center(
+      return Padding(
+        padding: EdgeInsets.only(bottom: shellBottom),
+        child: Center(
           child: Column(
             mainAxisSize: MainAxisSize.min,
             children: [
@@ -211,13 +225,19 @@ class _HistoryScreenState extends State<HistoryScreen> {
               ),
             ],
           ),
+        ),
       );
     }
     if (_loading) {
-      return const Center(child: CircularProgressIndicator());
+      return Padding(
+        padding: EdgeInsets.only(bottom: shellBottom),
+        child: const Center(child: CircularProgressIndicator()),
+      );
     }
     if (_error != null) {
-      return Center(
+      return Padding(
+        padding: EdgeInsets.only(bottom: shellBottom),
+        child: Center(
           child: Column(
             mainAxisSize: MainAxisSize.min,
             children: [
@@ -225,6 +245,7 @@ class _HistoryScreenState extends State<HistoryScreen> {
               TextButton(onPressed: _load, child: const Text('Retry')),
             ],
           ),
+        ),
       );
     }
     return RefreshIndicator(
@@ -237,14 +258,17 @@ class _HistoryScreenState extends State<HistoryScreen> {
           ),
           if (_items.isEmpty)
             SliverFillRemaining(
+              child: Padding(
+                padding: EdgeInsets.only(bottom: shellBottom),
                 child: Center(
                   child: Text('No tasks yet.',
                       style: GoogleFonts.inter(color: PencilTheme.inkSoft)),
                 ),
+              ),
             )
           else
             SliverPadding(
-              padding: const EdgeInsets.fromLTRB(16, 0, 16, 28),
+              padding: EdgeInsets.fromLTRB(16, 0, 16, 28 + shellBottom),
               sliver: SliverGrid(
                 gridDelegate: const SliverGridDelegateWithFixedCrossAxisCount(
                   crossAxisCount: 2,

lib/features/home/home_screen.dart

@@ -368,10 +368,10 @@ class _HomeScreenState extends State<HomeScreen> {
           SafeArea(
             bottom: false,
             child: Padding(
-              padding: const EdgeInsets.only(
+              padding: EdgeInsets.only(
                 left: 16,
                 right: 16,
-                bottom: 16,
+                bottom: 16 + PencilTheme.mainTabBottomChromeReserve(context),
               ),
               child: Column(
                 crossAxisAlignment: CrossAxisAlignment.stretch,
@@ -663,6 +663,8 @@ class _HomeScreenState extends State<HomeScreen> {
                                           fontWeight: FontWeight.w600,
                                           color: PencilTheme.homeTextPrimary
                                               .withValues(alpha: 0.85),
+                                          shadows:
+                                              PencilTheme.homeCreditsTextShadows,
                                         ),
                                       ),
                                       const SizedBox(height: 12),

lib/features/profile/profile_screen.dart

@@ -72,7 +72,12 @@ class _ProfileScreenState extends State<ProfileScreen> {
               ),
               Expanded(
                 child: ListView(
-                  padding: const EdgeInsets.only(bottom: 28),
+                  padding: EdgeInsets.only(
+                    bottom: 28 +
+                        (widget.isRootTab
+                            ? PencilTheme.mainTabBottomChromeReserve(context)
+                            : 0),
+                  ),
                   children: [
                     Padding(
                       padding: const EdgeInsets.fromLTRB(20, 16, 20, 8),

lib/features/purchase/purchase_screen.dart

@@ -769,6 +769,16 @@ class _ProductCard extends StatelessWidget {
     return ((1 - a / o) * 100).round();
   }
 
+  /// 展示用：金额前加 `$`（已有 `$` / `¥` 则不改）。
+  static String _withDollarPrefix(String amount) {
+    final t = amount.trim();
+    if (t.isEmpty || t == '—') return t;
+    if (t.startsWith(r'$') || t.startsWith('¥') || t.startsWith('￥')) {
+      return t;
+    }
+    return r'$' + t;
+  }
+
   @override
   Widget build(BuildContext context) {
     final rawTitle = item.title;
@@ -809,13 +819,13 @@ class _ProductCard extends StatelessWidget {
                       creditsTopLabel,
                       style: GoogleFonts.inter(
                         fontSize: 13,
-                        fontWeight: FontWeight.w600,
+                        fontWeight: FontWeight.w800,
                         color: PencilTheme.stone600,
                       ),
                     ),
                     const SizedBox(height: 8),
                     Text(
-                      actual,
+                      _withDollarPrefix(actual),
                       style: GoogleFonts.inter(
                         fontSize: 26,
                         fontWeight: FontWeight.w800,
@@ -834,7 +844,7 @@ class _ProductCard extends StatelessWidget {
                           borderRadius: BorderRadius.circular(8),
                         ),
                         child: Text(
-                          origin,
+                          _withDollarPrefix(origin),
                           style: GoogleFonts.inter(
                             fontSize: 12,
                             fontWeight: FontWeight.w600,

lib/features/shell/main_screen.dart

@@ -1,13 +1,21 @@
 import 'dart:async';
 
 import 'package:flutter/material.dart';
+import 'package:google_fonts/google_fonts.dart';
 
 import '../../core/auth/auth_service.dart';
 import '../../core/payment/google_play_order_recovery.dart';
+import '../../core/theme/app_colors.dart';
 import '../history/history_screen.dart';
 import '../home/home_screen.dart';
 import '../profile/profile_screen.dart';
 
+/// 底栏：极淡背景渐变 + 图标/标签 [Shadow]，兼顾层次与可读性。
+const List<Shadow> _bottomNavItemShadows = [
+  Shadow(offset: Offset(0, 1), blurRadius: 3, color: Color(0x72000000)),
+  Shadow(offset: Offset(0, 0), blurRadius: 8, color: Color(0x40000000)),
+];
+
 /// Root shell: bottom tabs **Home**, **History**, **Profile** (English labels).
 class MainScreen extends StatefulWidget {
   const MainScreen({super.key});
@@ -38,19 +46,61 @@ class _MainScreenState extends State<MainScreen> {
 
   @override
   Widget build(BuildContext context) {
+    final parentNav = NavigationBarTheme.of(context);
     return Scaffold(
+      // All tabs: body extends under the bottom bar (faint gradient + [NavigationBar]).
+      extendBody: true,
       body: IndexedStack(
         index: _index,
         children: [
           const HomeScreen(),
-          HistoryScreen(
+          HistoryScreen(isRootTab: true, isTabSelected: _index == 1),
-            isRootTab: true,
-            isTabSelected: _index == 1,
-          ),
           const ProfileScreen(isRootTab: true),
         ],
       ),
-      bottomNavigationBar: NavigationBar(
+      bottomNavigationBar: Stack(
+        alignment: Alignment.bottomCenter,
+        children: [
+          Positioned.fill(
+            child: DecoratedBox(
+              decoration: BoxDecoration(
+                gradient: LinearGradient(
+                  begin: Alignment.bottomCenter,
+                  end: Alignment.topCenter,
+                  colors: [
+                    AppColors.surface.withValues(alpha: 0.40),
+                    AppColors.surface.withValues(alpha: 0.15),
+                    AppColors.surface.withValues(alpha: 0),
+                  ],
+                  stops: const [0.0, 0.48, 1.0],
+                ),
+              ),
+            ),
+          ),
+          NavigationBarTheme(
+            data: parentNav.copyWith(
+              labelTextStyle: WidgetStateProperty.resolveWith((states) {
+                final selected = states.contains(WidgetState.selected);
+                return GoogleFonts.inter(
+                  fontSize: 12,
+                  fontWeight: selected ? FontWeight.w600 : FontWeight.w500,
+                  color: selected ? AppColors.primary : AppColors.onSurface,
+                  shadows: _bottomNavItemShadows,
+                );
+              }),
+              iconTheme: WidgetStateProperty.resolveWith((states) {
+                final selected = states.contains(WidgetState.selected);
+                return IconThemeData(
+                  color: selected ? AppColors.primary : AppColors.onSurface,
+                  shadows: _bottomNavItemShadows,
+                );
+              }),
+            ),
+            child: NavigationBar(
+              backgroundColor: Colors.transparent,
+              elevation: 0,
+              surfaceTintColor: Colors.transparent,
+              shadowColor: Colors.transparent,
               selectedIndex: _index,
               onDestinationSelected: (i) => setState(() => _index = i),
               destinations: const [
@@ -71,6 +121,9 @@ class _MainScreenState extends State<MainScreen> {
                 ),
               ],
             ),
+          ),
+        ],
+      ),
     );
   }
 }

lib/widgets/pencil_chrome.dart

@@ -67,6 +67,7 @@ class PencilGlassCreditsPill extends StatelessWidget {
             fontSize: 15,
             fontWeight: FontWeight.w600,
             color: PencilTheme.homeTextPrimary,
+            shadows: PencilTheme.homeCreditsTextShadows,
           ),
         ),
       ],