首页左右侧边栏添加深蓝渐变背景蒙层

src/layouts/DashboardLayout.vue

@@ -299,6 +299,7 @@ export default {
     height: 100%;
     display: flex;
     flex-direction: column;
+    background: linear-gradient(180deg, rgba(10, 25, 60, 0.75) 0%, rgba(5, 15, 40, 0.85) 100%);
 }
 
 /* --- 中心区域保持事件穿透，让出地图的拖拽控制权 --- */