fix: 为小屏手机优化购物车布局

- 订单摘要放在顶部，商品列表在下方
- 商品项使用卡片式布局
- 复选框和删除按钮绝对定位
- 图片缩小为45px，更紧凑
- 各元素尺寸适配375px宽度

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/views/user/Cart.vue

@@ -932,9 +932,24 @@ onMounted(() => {
 
 @media (max-width: 768px) {
   .cart-page {
-    padding-bottom: 20px;
+    padding: 8px !important;
-    padding-left: 8px;
+    padding-bottom: 16px !important;
-    padding-right: 8px;
+  }
+
+  .cart-container {
+    display: flex !important;
+    flex-direction: column !important;
+    gap: 12px !important;
+  }
+
+  .cart-left {
+    order: 2 !important;
+  }
+
+  .cart-summary-panel {
+    order: 1 !important;
+    position: static !important;
+    margin-bottom: 0 !important;
   }
 
   .cart-header {
@@ -946,39 +961,34 @@ onMounted(() => {
     overflow: visible !important;
   }
 
-  /* 商品项 - 使用grid两行布局 */
+  /* 商品项 - 卡片式布局 */
   .cart-item {
-    display: grid !important;
+    display: flex !important;
-    grid-template-columns: 50px 1fr auto !important;
+    flex-direction: column !important;
-    grid-template-rows: auto auto !important;
+    padding: 10px !important;
+    position: relative !important;
     gap: 8px !important;
-    padding: 12px !important;
+    min-width: 0 !important;
-    align-items: center !important;
   }
 
-  /* 复选框 - 第一行第一列 */
+  /* 复选框 - 绝对定位左上角 */
   .cart-item > .el-checkbox {
-    grid-column: 1 !important;
+    position: absolute !important;
-    grid-row: 1 / 3 !important;
+    top: 8px !important;
-    width: 50px !important;
+    left: 8px !important;
-    justify-self: center !important;
+    z-index: 10 !important;
   }
 
-  /* 商品图片+信息 - 第一行第二列 */
+  /* 商品图片+名称 - 第一行 */
   .cart-item > .item-product {
-    grid-column: 2 !important;
-    grid-row: 1 !important;
     display: flex !important;
     flex-direction: row !important;
+    align-items: flex-start !important;
     gap: 8px !important;
-    align-items: center !important;
+    padding-left: 32px !important;
-  }
+    padding-right: 50px !important;
-
+    min-width: 0 !important;
-  /* 删除按钮 - 第一行第三列 */
+    width: 100% !important;
-  .cart-item > .item-action {
-    grid-column: 3 !important;
-    grid-row: 1 !important;
-    justify-self: end !important;
   }
 
   /* 隐藏单价 */
@@ -986,39 +996,54 @@ onMounted(() => {
     display: none !important;
   }
 
-  /* 数量 - 第二行第二列 */
+  /* 删除按钮 - 绝对定位右上角 */
+  .cart-item > .item-action {
+    position: absolute !important;
+    top: 8px !important;
+    right: 8px !important;
+    z-index: 10 !important;
+  }
+
+  /* 数量+小计 - 第二行 */
   .cart-item > .item-quantity {
-    grid-column: 2 !important;
-    grid-row: 2 !important;
     display: flex !important;
     flex-direction: row !important;
     align-items: center !important;
-    gap: 8px !important;
+    justify-content: space-between !important;
+    padding-left: 32px !important;
+    width: 100% !important;
   }
 
-  /* 小计 - 第二行第三列 */
+  /* 小计放在数量行的右侧 */
   .cart-item > .item-subtotal {
-    grid-column: 3 !important;
+    display: none !important;
-    grid-row: 2 !important;
+  }
-    justify-self: end !important;
+
-    text-align: right !important;
+  /* 在数量行内显示价格 */
+  .item-quantity::after {
+    content: "¥" attr(data-price);
+    font-size: 14px;
+    font-weight: 600;
+    color: #f56c6c;
   }
 
   .item-product .item-image {
-    width: 50px !important;
+    width: 45px !important;
-    height: 50px !important;
+    height: 45px !important;
     flex-shrink: 0 !important;
   }
 
   .item-info {
     flex: 1 !important;
     min-width: 0 !important;
+    overflow: hidden !important;
   }
 
   .item-name {
-    font-size: 14px !important;
+    font-size: 13px !important;
     line-height: 1.3 !important;
-    -webkit-line-clamp: 1 !important;
+    margin-bottom: 2px !important;
+    word-break: break-all !important;
   }
 
   .item-tags {
@@ -1026,84 +1051,90 @@ onMounted(() => {
   }
 
   .item-quantity :deep(.el-input-number) {
-    width: 90px !important;
+    width: 80px !important;
   }
 
   .item-quantity .stock-tip {
-    font-size: 11px !important;
+    display: none !important;
-  }
-
-  .item-subtotal .subtotal-price {
-    font-size: 14px !important;
-    font-weight: 600 !important;
-    color: #f56c6c !important;
-    white-space: nowrap !important;
-  }
-
-  /* 支付方式 */
-  .payment-methods {
-    grid-template-columns: repeat(2, 1fr) !important;
-  }
-
-  .cart-left {
-    gap: 10px !important;
   }
 
+  /* 地址 */
   .checkout-section {
     padding: 10px !important;
   }
 
   .section-title {
-    font-size: 14px !important;
+    font-size: 13px !important;
-    margin-bottom: 10px !important;
+    margin-bottom: 8px !important;
   }
 
+  .address-item {
+    padding: 8px !important;
+  }
+
+  .address-name {
+    font-size: 13px !important;
+  }
+
+  .address-phone {
+    font-size: 12px !important;
+  }
+
+  .address-detail {
+    font-size: 11px !important;
+  }
+
+  /* 支付方式 */
+  .payment-methods {
+    grid-template-columns: repeat(2, 1fr) !important;
+    gap: 6px !important;
+  }
+
+  .payment-item {
+    padding: 8px 4px !important;
+  }
+
+  .payment-icon {
+    font-size: 20px !important;
+  }
+
+  .payment-name {
+    font-size: 11px !important;
+  }
+
+  /* 订单摘要 */
   .cart-summary-panel {
     padding: 10px !important;
   }
 
   .summary-title {
-    font-size: 15px !important;
+    font-size: 14px !important;
-    margin-bottom: 10px !important;
+    margin-bottom: 8px !important;
-    padding-bottom: 8px !important;
+    padding-bottom: 6px !important;
   }
 
   .summary-row {
-    font-size: 13px !important;
+    font-size: 12px !important;
-    margin-bottom: 8px !important;
+    margin-bottom: 6px !important;
   }
 
   .summary-total .total-amount {
-    font-size: 18px !important;
+    font-size: 16px !important;
+  }
+
+  .summary-count {
+    font-size: 12px !important;
+    margin-bottom: 8px !important;
   }
 
   .checkout-btn {
-    height: 42px !important;
+    height: 38px !important;
-    font-size: 15px !important;
-  }
-
-  .address-item {
-    padding: 10px !important;
-  }
-
-  .address-name {
     font-size: 14px !important;
   }
 
-  .address-detail {
+  .summary-actions {
-    font-size: 12px !important;
+    margin-top: 8px !important;
-  }
+    padding-top: 8px !important;
-
-  .payment-item {
-    padding: 12px 8px !important;
-  }
-
-  .payment-icon {
-    font-size: 24px !important;
-  }
-
-  .payment-name {
-    font-size: 13px !important;
   }
 }
 </style>