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/trade/components/amount_input.dart

@@ -63,7 +63,7 @@ class _AmountInputState extends State<AmountInput> {
         Container(
           height: 48,
           decoration: BoxDecoration(
-            color: colorScheme.surfaceContainerHighest.withOpacity(0.3),
+            color: colorScheme.surfaceContainerHighest.withOpacity(0.5), // 调整透明度
             borderRadius: BorderRadius.circular(AppRadius.md),
           ),
           child: TextField(

flutter_monisuo/lib/ui/pages/trade/components/trade_button.dart

@@ -5,7 +5,7 @@ import '../../../../core/theme/app_theme.dart';
 
 /// 交易按钮组件
 ///
-/// CTA 买入/卖出按钮。profit-green底 / sell-red底，圆角lg，高48，白字16px bold。
+/// CTA 买入/卖出按钮。profit-green底 / sell-red底，圆角lg，高48，买入白字/卖出红字16px bold。
 class TradeButton extends StatelessWidget {
   final bool isBuy;
   final String? coinCode;
@@ -27,6 +27,10 @@ class TradeButton extends StatelessWidget {
     final colorScheme = Theme.of(context).colorScheme;
     final fillColor =
         isBuy ? AppColorScheme.buyButtonFill : AppColorScheme.sellButtonFill;
+    // 买入按钮文字为白色，卖出按钮文字为红色
+    final textColor = isBuy
+        ? Colors.white
+        : (enabled ? AppColorScheme.sellButtonFill : colorScheme.onSurface.withOpacity(0.3));
 
     return GestureDetector(
       onTap: enabled ? onPressed : null,
@@ -39,19 +43,19 @@ class TradeButton extends StatelessWidget {
         ),
         child: Center(
           child: isLoading
-              ? const SizedBox(
+              ? SizedBox(
                   width: 20,
                   height: 20,
                   child: CircularProgressIndicator(
                     strokeWidth: 2,
-                    color: AppColorScheme.darkOnPrimary,
+                    color: isBuy ? Colors.white : AppColorScheme.sellButtonFill,
                   ),
                 )
               : Text(
                   '${isBuy ? '买入' : '卖出'} ${coinCode ?? ""}',
                   style: AppTextStyles.headlineLarge(context).copyWith(
                     color: enabled
-                        ? AppColorScheme.darkOnPrimary
+                        ? textColor
                         : colorScheme.onSurface.withOpacity(0.3),
                   ),
                 ),

flutter_monisuo/lib/ui/pages/trade/components/trade_form_card.dart

@@ -207,7 +207,7 @@ class TradeFormCard extends StatelessWidget {
         child: Container(
           height: 32,
           decoration: BoxDecoration(
-            color: context.colors.surfaceContainerHighest, // 移除 0.5 透明度
+            color: context.colors.surfaceContainerHighest.withOpacity(0.5), // 更柔和的颜色
             borderRadius: BorderRadius.circular(AppRadius.sm),
           ),
           child: Center(

flutter_monisuo/lib/ui/pages/trade/trade_page.dart

@@ -121,7 +121,7 @@ class _TradePageState extends State<TradePage>
           return SafeArea(
             child: SingleChildScrollView(
               padding: const EdgeInsets.fromLTRB(
-                AppSpacing.md, 0, AppSpacing.md, AppSpacing.xl + AppSpacing.sm,
+                AppSpacing.md, AppSpacing.md, AppSpacing.md, AppSpacing.xl + AppSpacing.sm, // 添加顶部间距
               ),
               child: Column(
                 children: [