背景色优化

css/nav-mega-menu.css

@@ -6,7 +6,7 @@
   top: 100%;
   left: 0;
   width: 100%;
-  background: #fff;
+  background: linear-gradient(to bottom, #f8fbff 0%, #fff 100%);
   box-shadow: 0 4px 16px rgba(0, 0, 0, 0.1);
   z-index: 1000;
   overflow: hidden;
@@ -83,7 +83,7 @@
 .nav-right-content {
   flex: 1;
   padding: 24px 32px;
-  background: #fff;
+  background: linear-gradient(135deg, #fafcff 0%, #ffffff 100%);
   overflow-y: auto;
   max-height: 500px;
 }
@@ -112,19 +112,21 @@
 /* 三级菜单网格布局 */
 .nav-third-grid {
   display: grid;
-  grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
-  gap: 12px 20px;
+  grid-template-columns: repeat(3, 1fr);
+  gap: 12px 24px;
   margin-top: 20px;
 }
 
 /* 三级菜单项 */
 .nav-third-item {
   margin: 0;
+  width: 100%;
 }
 
 .nav-third-link {
   display: flex;
   align-items: center;
+  width: 100%;
   padding: 10px 12px;
   border-radius: 4px;
   color: #333;
@@ -132,10 +134,11 @@
   text-decoration: none;
   transition: all 0.2s ease;
   border: 1px solid transparent;
+  box-sizing: border-box;
 }
 
 .nav-third-link:hover {
-  background: #f0f7ff;
+  background: #e6f7ff;
   border-color: #91d5ff;
   color: #1890ff;
   transform: translateX(4px);