Reapply "codex 试用，美化"

This reverts commit f8738f2928.

admin/dashboard/templates/base.html

@@ -43,16 +43,26 @@
         .header {
             height: 58px;
             padding: 0 16px;
-            background: #ffffff;
-            border-bottom: 1px solid #e5e6eb;
+            background: #0b1d33;
+            border-bottom: 1px solid #0f2a4a;
             display: flex;
             align-items: center;
             justify-content: space-between;
-            box-shadow: 0 2px 6px rgba(0,0,0,0.04);
+            box-shadow: 0 2px 10px rgba(0, 163, 255, 0.12);
             position: sticky;
             top: 0;
             z-index: 100;
         }
+        .header::after {
+            content: "";
+            position: absolute;
+            left: 12px;
+            right: 12px;
+            bottom: 0;
+            height: 1px;
+            background: rgba(91, 211, 255, 0.35);
+            box-shadow: 0 0 8px rgba(91, 211, 255, 0.4);
+        }
 
         .header-left {
             display: flex;
@@ -63,6 +73,7 @@
             width: 36px;
             height: 36px;
             margin-right: 8px;
+            filter: drop-shadow(0 0 6px rgba(91, 211, 255, 0.35));
         }
 
         .header-right {
@@ -73,16 +84,20 @@
         .user-info {
             margin-right: 8px;
             font-size: 14px;
-            color: #444;
+            color: #cfe6ff;
         }
 
         .logout-btn {
-            color: #444;
+            color: #9fd7ff;
             font-weight: 500;
             transition: 0.2s;
         }
         .logout-btn:hover {
-            color: #000;
+            color: #5bd3ff;
+        }
+        .header h2 {
+            color: #e6f3ff;
+            letter-spacing: 0.5px;
         }
 
         /* ------------------------------