优化功能菜单布局：手机端2列，PC端横版

src/pages/index/index.vue

@@ -413,20 +413,28 @@ export default {
 .menu-grid {
   display: flex;
   flex-wrap: wrap;
-  justify-content: space-between;
 }
 
+/* 手机端 - 2列布局 */
 .menu-card {
-  width: 48%;
+  width: 44%;
   background: #fff;
   border-radius: 24rpx;
   padding: 30rpx;
-  margin-bottom: 20rpx;
+  margin: 10rpx;
   box-shadow: 0 8rpx 30rpx rgba(0, 0, 0, 0.1);
   display: flex;
   flex-direction: column;
 }
 
+/* 平板/PC端 - 横版布局，超过4个换行 */
+@media (min-width: 768px) {
+  .menu-card {
+    width: 22%;
+    margin: 10rpx;
+  }
+}
+
 .menu-card:active {
   transform: scale(0.98);
   opacity: 0.9;