fix: 修复UI样式问题

- 首页：移除盈亏日历，福利中心卡片改为白色背景，查看按钮改为黄色
- 资产页面：余额卡片撑满宽度
- 底部导航栏：移除背景高亮，只保留图标和文字变化
- 行情页面：调整卡片文字大小和柱形图样式
- 交易页面：买入按钮白色文字，卖出按钮红色文字，优化输入框和百分比卡片样式，添加顶部间距
- 全局：移除渐变色，统一使用纯色背景

flutter_monisuo/lib/ui/pages/asset/components/balance_card.dart

@@ -26,33 +26,36 @@ class BalanceCard extends StatelessWidget {
         ? (provider.fundAccount?.balance ?? provider.overview?.fundBalance ?? '0.00')
         : _calculateTradeTotal();
 
-    return GlassPanel(
-      padding: const EdgeInsets.all(20),
-      borderRadius: BorderRadius.circular(AppRadius.lg),
-      child: Column(
-        crossAxisAlignment: CrossAxisAlignment.start,
-        children: [
-          Text(
-            'USDT 余额',
-            style: AppTextStyles.bodyMedium(context).copyWith(
-              color: context.colors.onSurfaceVariant,
-              fontWeight: FontWeight.w400,
+    return SizedBox(
+      width: double.infinity, // 确保卡片撑满宽度
+      child: GlassPanel(
+        padding: const EdgeInsets.all(20),
+        borderRadius: BorderRadius.circular(AppRadius.lg),
+        child: Column(
+          crossAxisAlignment: CrossAxisAlignment.start,
+          children: [
+            Text(
+              'USDT 余额',
+              style: AppTextStyles.bodyMedium(context).copyWith(
+                color: context.colors.onSurfaceVariant,
+                fontWeight: FontWeight.w400,
+              ),
             ),
-          ),
-          const SizedBox(height: 12),
-          Text(
-            _formatBalance(displayBalance),
-            style: AppTextStyles.numberLarge(context),
-          ),
-          const SizedBox(height: 12),
-          Text(
-            '\u2248 \$${_formatBalance(displayBalance)} USD',
-            style: AppTextStyles.bodyMedium(context).copyWith(
-              color: context.appColors.onSurfaceMuted,
-              fontWeight: FontWeight.w400,
+            const SizedBox(height: 12),
+            Text(
+              _formatBalance(displayBalance),
+              style: AppTextStyles.numberLarge(context),
             ),
-          ),
-        ],
+            const SizedBox(height: 12),
+            Text(
+              '\u2248 \$${_formatBalance(displayBalance)} USD',
+              style: AppTextStyles.bodyMedium(context).copyWith(
+                color: context.appColors.onSurfaceMuted,
+                fontWeight: FontWeight.w400,
+              ),
+            ),
+          ],
+        ),
       ),
     );
   }