🔧 Fix remaining white sections in admin-dashboard

- Fixed .modal-content background to dark theme
- Fixed .link-stat-card background to dark theme
- Updated text colors in link statistics cards
- Changed close button color to match dark theme
- All sections now consistently use dark design

public/css/admin-dashboard.css

@@ -202,17 +202,18 @@ body {
 }
 
 .modal-content {
-    background-color: white;
+    background-color: rgba(26, 26, 46, 0.95);
     margin: 10% auto;
     padding: 20px;
     border-radius: 10px;
     width: 90%;
     max-width: 500px;
     position: relative;
+    border: 1px solid rgba(255, 255, 255, 0.1);
 }
 
 .close {
-    color: #aaa;
+    color: #8892b0;
     float: right;
     font-size: 28px;
     font-weight: bold;
@@ -435,21 +436,22 @@ body {
 
 .link-stat-card {
     text-align: center;
-    background: white;
+    background: rgba(26, 26, 46, 0.95);
     border-radius: 8px;
     padding: 20px;
-    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
+    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
+    border: 1px solid rgba(255, 255, 255, 0.1);
 }
 
 .link-stat-number {
     font-size: 2em;
     font-weight: bold;
-    color: #1e3c72;
+    color: #00d4ff;
     margin-bottom: 8px;
 }
 
 .link-stat-label {
-    color: #6c757d;
+    color: #8892b0;
     font-size: 0.9em;
     font-weight: 500;
 }