feat(ui): 新增确认对话框组件并优化结账页面

- 新增 `ConfirmDialog` 组件，用于确认删除操作
- 在 `CheckoutPage` 中集成 `ConfirmDialog`，支持删除单个商品和清空购物车
- 优化 `FrostedGlass` 组件，支持自定义背景透明度和模糊级别
- 改进结账页面的表单验证和错误处理逻辑

+<template>
+  <Teleport to="body">
+    <div
+      v-if="show"
+      class="fixed inset-0 z-50 flex items-center justify-center px-4"
+    >
+      <div
+        class="fixed inset-0 bg-black/50 backdrop-blur-sm"
+        @click="handleCancel"
+      ></div>
+      <FrostedGlass class="w-full max-w-sm p-6 relative z-10" :bg-opacity="90" blur-level="md">
+        <h3 class="text-lg font-medium mb-2">{{ title }}</h3>
+        <p class="text-gray-600 text-sm mb-6">{{ message }}</p>
+        <div class="flex justify-end space-x-3">
+          <button
+            @click="handleCancel"
+            class="px-4 py-2 text-sm text-gray-600 hover:text-gray-800"
+          >
+            取消
+          </button>
+          <button
+            @click="handleConfirm"
+            class="px-4 py-2 text-sm text-white bg-red-500 hover:bg-red-600 rounded-lg"
+          >
+            确认
+          </button>
+        </div>
+      </FrostedGlass>
+    </div>
+  </Teleport>
+</template>
+
+<script setup>
+import { defineProps, defineEmits } from 'vue'
+import FrostedGlass from './FrostedGlass.vue'
+
+const props = defineProps({
+  show: {
+    type: Boolean,
+    default: false
+  },
+  title: {
+    type: String,
+    default: '确认'
+  },
+  message: {
+    type: String,
+    required: true
+  }
+})
+
+const emit = defineEmits(['confirm', 'cancel', 'update:show'])
+
+const handleConfirm = () => {
+  emit('confirm')
+  emit('update:show', false)
+}
+
+const handleCancel = () => {
+  emit('cancel')
+  emit('update:show', false)
+}
+</script>

 <template>
   <div
     :class="[
-      'bg-white/20 backdrop-blur-md rounded-xl border border-white/30 shadow-lg',
+      `bg-white/${bgOpacity} backdrop-blur-${blurLevel} rounded-xl border border-white/30 shadow-lg`,
       className
     ]"
   >
@@ -16,6 +16,16 @@ defineProps({
   className: {
     type: String,
     default: ''
+  },
+  bgOpacity: {
+    type: Number,
+    default: 80,
+    validator: (value) => value >= 0 && value <= 100
+  },
+  blurLevel: {
+    type: String,
+    default: 'sm',
+    validator: (value) => ['none', 'sm', 'md', 'lg', 'xl', '2xl', '3xl'].includes(value)
   }
 })
 </script>

@@ -51,12 +51,24 @@
                     @error="handleImageError"
                   />
                 </div>
-                <div>
+                <div class="flex-1">
                   <p class="font-medium text-sm line-clamp-1">{{ item.title }}</p>
                   <p class="text-xs text-gray-500">
                     {{ item.type === 'course' ? '课程' : '活动' }} · {{ item.quantity }} 份
                   </p>
                 </div>
+                <button
+                  @click="() => {
+                    itemToDelete = item
+                    showConfirmDialog = true
+                  }"
+                  class="text-red-500 hover:text-red-600 p-1 -mr-1"
+                  title="删除"
+                >
+                  <svg xmlns="http://www.w3.org/2000/svg" class="h-4 w-4" fill="none" viewBox="0 0 24 24" stroke="currentColor">
+                    <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M19 7l-.867 12.142A2 2 0 0116.138 21H7.862a2 2 0 01-1.995-1.858L5 7m5 4v6m4-6v6m1-10V4a1 1 0 00-1-1h-4a1 1 0 00-1 1v3M4 7h16" />
+                  </svg>
+                </button>
               </div>
               <div class="ml-2 text-right">
                 <p class="font-medium text-sm">{{ formatPrice(item.price * item.quantity) }}</p>
@@ -204,7 +216,10 @@
               </div>
               <button
                 type="button"
-                @click="clearCart"
+                @click="() => {
+                  showConfirmDialog = true
+                  itemToDelete = null
+                }"
                 class="text-sm text-red-500"
               >
                 清空购物车
@@ -227,6 +242,26 @@
         </form>
       </div>
     </div>
+
+    <!-- Confirm Dialog -->
+    <ConfirmDialog
+      v-model:show="showConfirmDialog"
+      title="确认删除"
+      :message="itemToDelete ? `确定要删除 ${itemToDelete.title || '此商品'} 吗？` : '确定要清空购物车吗？'"
+      @confirm="() => {
+        if (itemToDelete) {
+          if (cartItems.length === 1) {
+            clearCart()
+          } else {
+            removeFromCart(itemToDelete.id, itemToDelete.type)
+          }
+          itemToDelete = null
+        } else {
+          clearCart()
+        }
+      }"
+      @cancel="itemToDelete = null"
+    />
   </AppLayout>
 </template>
 
@@ -235,10 +270,11 @@ import { ref } from 'vue'
 import { useRouter } from 'vue-router'
 import AppLayout from '@/components/layout/AppLayout.vue'
 import FrostedGlass from '@/components/ui/FrostedGlass.vue'
+import ConfirmDialog from '@/components/ui/ConfirmDialog.vue'
 import { useCart } from '@/contexts/cart'
 
 const router = useRouter()
-const { items: cartItems, getTotalPrice, handleCheckout, clearCart } = useCart()
+const { items: cartItems, getTotalPrice, handleCheckout, clearCart, removeFromCart } = useCart()
 
 // Form state
 const formData = ref({
@@ -255,6 +291,10 @@ const isProcessing = ref(false)
 const orderComplete = ref(false)
 const orderId = ref('')
 
+// Confirm dialog state
+const showConfirmDialog = ref(false)
+const itemToDelete = ref(null)
+
 // Format price with Chinese Yuan symbol
 const formatPrice = (price) => {
   return `¥${price.toFixed(2)}`
@@ -267,24 +307,39 @@ const handleImageError = (e) => {
 
 // Handle form submission
 const handleSubmit = async (e) => {
-  if (!formData.value.name || !formData.value.phone || !formData.value.address) {
-    alert('请填写必要信息')
-    return
-  }
+  try {
+    // 表单验证
+    if (!formData.value.name?.trim()) {
+      throw new Error('请输入姓名')
+    }
+    if (!formData.value.phone?.trim()) {
+      throw new Error('请输入手机号码')
+    }
+    if (!formData.value.address?.trim()) {
+      throw new Error('请输入联系地址')
+    }
+    if (!formData.value.paymentMethod) {
+      throw new Error('请选择支付方式')
+    }
 
-  isProcessing.value = true
+    isProcessing.value = true
 
-  try {
     // Process checkout
     const result = await handleCheckout(formData.value)
 
+    if (!result) {
+      throw new Error('支付处理失败，请重试')
+    }
+
     if (result.success) {
-      orderId.value = result.orderId
+      orderId.value = result.orderId || ''
       orderComplete.value = true
+    } else {
+      throw new Error(result.message || '支付失败，请重试')
     }
   } catch (error) {
     console.error('Checkout failed:', error)
-    alert('支付失败，请重试')
+    alert(error.message || '支付失败，请重试')
   } finally {
     isProcessing.value = false
   }