feat(ui): 优化组件样式并添加现代弹窗模板

- 更新 trade_button.dart 使用新颜色系统
- 更新 coin_card.dart 使用新颜色系统
- 更新 asset_card.dart 使用新颜色系统
- 创建 modern_dialog.dart 现代弹窗模板
- 创建 modern_bottom_sheet.dart 现代底部抽屉模板

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

flutter_monisuo/lib/ui/components/asset_card.dart

@@ -1,6 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:shadcn_ui/shadcn_ui.dart';
-import '../../core/theme/app_colors.dart';
+import '../../core/theme/app_color_scheme.dart';
 
 /// 资产卡片组件 - 用于显示资产总览
 class AssetCard extends StatelessWidget {
@@ -13,9 +13,9 @@ class AssetCard extends StatelessWidget {
   final Gradient? gradient;
   final VoidCallback? onTap;
 
-  // 默认渐变色 - 使用品牌蓝
+  // 默认渐变色 - 使用品牌青绿色
   static const defaultGradient = LinearGradient(
-    colors: [Color(0xFF2563EB), Color(0xFF1D4ED8)],
+    colors: [AppColorScheme.primaryDark, Color(0xFF00B894)],
     begin: Alignment.topLeft,
     end: Alignment.bottomRight,
   );
@@ -54,7 +54,7 @@ class AssetCard extends StatelessWidget {
           borderRadius: BorderRadius.circular(20),
           boxShadow: [
             BoxShadow(
-              color: Colors.black.withOpacity(0.1),
+              color: Colors.black.withValues(alpha: 0.1),
               blurRadius: 10,
               offset: const Offset(0, 4),
             ),
@@ -72,7 +72,7 @@ class AssetCard extends StatelessWidget {
                 ),
                 const Spacer(),
                 if (onTap != null)
-                  Icon(
+                  const Icon(
                     LucideIcons.chevronRight,
                     color: Colors.white70,
                     size: 18,
@@ -161,9 +161,6 @@ class AssetCardCompact extends StatelessWidget {
   final bool? isUp;
   final VoidCallback? onTap;
 
-  static const upColor = Color(0xFF00C853);
-  static const downColor = Color(0xFFFF5252);
-
   const AssetCardCompact({
     super.key,
     required this.title,
@@ -176,6 +173,7 @@ class AssetCardCompact extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     final theme = ShadTheme.of(context);
+    final isValueUp = isUp ?? true;
 
     return ShadCard(
       padding: const EdgeInsets.all(16),
@@ -205,13 +203,13 @@ class AssetCardCompact extends StatelessWidget {
               Container(
                 padding: const EdgeInsets.symmetric(horizontal: 10, vertical: 6),
                 decoration: BoxDecoration(
-                  color: (isUp ?? true) ? upColor.withOpacity(0.2) : downColor.withOpacity(0.2),
+                  color: getChangeBackgroundColor(isValueUp),
                   borderRadius: BorderRadius.circular(6),
                 ),
                 child: Text(
                   change!,
                   style: TextStyle(
-                    color: (isUp ?? true) ? upColor : downColor,
+                    color: getChangeColor(isValueUp),
                     fontWeight: FontWeight.w600,
                   ),
                 ),