style(Rewards): 优化商品列表的布局和样式

- 调整商品信息区域布局，使标题和商家名称独占一行
- 修改兑换按钮样式，增加渐变和阴影效果
- 优化间距和字体样式，提升整体视觉效果

@@ -65,15 +65,27 @@
           <!-- 商品列表 -->
           <template v-else>
             <view v-for="reward in sortedRewardItems" :key="reward.id"
-              class="bg-white rounded-xl p-4 flex items-center shadow-[0_2px_8px_rgba(0,0,0,0.08)]">
-              <image :src="reward.thumbnail" class="w-16 h-16 rounded-lg mr-4 flex-shrink-0" mode="aspectFill" />
-              <view class="flex-1 min-w-0">
-                <view class="font-medium text-base">{{ reward.title }}</view>
-                <view class="text-gray-500 text-sm mt-1">{{ reward.merchant_name }}</view>
+              class="bg-white rounded-xl p-4 shadow-[0_2px_8px_rgba(0,0,0,0.08)]">
+              <!-- 商品信息区域 -->
+              <view class="flex items-start mb-4">
+                <image :src="reward.thumbnail" class="w-20 h-20 rounded-lg mr-4 flex-shrink-0" mode="aspectFill" />
+                <view class="flex-1 min-w-0">
+                  <!-- 标题独占一行 -->
+                  <view class="font-medium text-base leading-5 mb-2 text-gray-900">{{ reward.title }}</view>
+                  <!-- 商家名称独占一行 -->
+                  <view class="text-gray-500 text-sm leading-4">{{ reward.merchant_name }}</view>
+                </view>
               </view>
-              <view class="ml-4 px-4 py-2 bg-blue-500 text-white rounded-lg text-sm flex-shrink-0"
-                @click="goToRewardDetail(reward)">
-                {{ reward.points_cost + '分兑换' }}
+
+              <!-- 兑换按钮区域 -->
+              <view class="flex items-center justify-between pt-3 border-t border-gray-100">
+                <view class="text-orange-500 font-semibold text-lg">
+                  {{ reward.points_cost }}积分
+                </view>
+                <view class="px-6 py-2 bg-gradient-to-r bg-blue-500 text-white rounded-full text-sm font-medium shadow-md active:shadow-sm transition-all duration-200"
+                  @click="goToRewardDetail(reward)">
+                  立即兑换
+                </view>
               </view>
             </view>