style: 完成前端专业金融风格优化

- 主题配色: 黑金传奇(暗) + 白金殿堂(亮)
- 底部导航: 去掉毛玻璃，简洁专业
- 交易页面: 明亮模式颜色优化，实心按钮
- 按钮圆角: xxl(24px) → lg(12px)/md(8px)
- 字体系统: Inter(币安同款)
- 整体风格: 专业金融科技

flutter_monisuo/lib/ui/pages/main/main_page.dart

@@ -1,4 +1,3 @@
-import 'dart:ui';
 import 'package:flutter/material.dart';
 import 'package:shadcn_ui/shadcn_ui.dart';
 import '../../../core/theme/app_spacing.dart';
@@ -96,7 +95,7 @@ class MainPageState extends State<MainPage> {
   }
 }
 
-/// 底部导航栏 - "The Kinetic Vault" 设计风格
+/// 底部导航栏 - 专业信任主题
 class _BottomNavBar extends StatelessWidget {
   final List<_NavItem> items;
   final int currentIndex;
@@ -114,22 +113,14 @@ class _BottomNavBar extends StatelessWidget {
 
     return Container(
       decoration: BoxDecoration(
-        color: colorScheme.surfaceContainerLow.withOpacity(0.8),
+        color: colorScheme.surfaceContainerLow,
         borderRadius: BorderRadius.vertical(top: Radius.circular(AppRadius.xxl + AppSpacing.sm)),
         border: Border(
           top: BorderSide(
             color: colorScheme.outlineVariant.withOpacity(0.15),
           ),
         ),
-        boxShadow: [
-          BoxShadow(
-            color: Colors.black.withOpacity(0.5),
-            blurRadius: 40, // 阴影效果保持固定
-            offset: const Offset(0, -10),
-          ),
-        ],
       ),
-      // 【优化】移除毛玻璃效果，保持简洁的半透明背景
       child: SafeArea(
         child: Padding(
           padding: EdgeInsets.fromLTRB(AppSpacing.md, AppSpacing.sm, AppSpacing.md, AppSpacing.lg),
@@ -176,13 +167,6 @@ class _NavItemWidget extends StatelessWidget {
             ? BoxDecoration(
                 color: colorScheme.primary.withOpacity(0.1),
                 borderRadius: BorderRadius.circular(AppSpacing.md),
-                boxShadow: [
-                  BoxShadow(
-                    color: colorScheme.primary.withOpacity(0.3),
-                    blurRadius: 15, // 发光效果保持固定
-                    spreadRadius: 0,
-                  ),
-                ],
               )
             : null,
         child: Column(