feat: Enhance loading indicator UI with custom spinners and improve download cancellation logic for custom downloaders.

templates/anime_downloader_linkkf_request.html

@@ -934,5 +934,43 @@
             z-index: 99999;
             opacity: 0.5;
         }
+        
+        /* 로딩 인디케이터 오버라이드 */
+        #loading {
+            background: rgba(15, 23, 42, 0.85) !important;
+            backdrop-filter: blur(8px) !important;
+        }
+        
+        #loading img {
+            display: none !important;
+        }
+        
+        #loading::after {
+            content: '';
+            width: 50px;
+            height: 50px;
+            border: 4px solid rgba(96, 165, 250, 0.2);
+            border-top-color: #60a5fa;
+            border-radius: 50%;
+            animation: loader-spin 0.8s linear infinite;
+        }
+        
+        @keyframes loader-spin {
+            to { transform: rotate(360deg); }
+        }
+        
+        #modal_loading img {
+            display: none !important;
+        }
+        
+        #modal_loading::after {
+            content: '';
+            width: 40px;
+            height: 40px;
+            border: 3px solid rgba(96, 165, 250, 0.2);
+            border-top-color: #60a5fa;
+            border-radius: 50%;
+            animation: loader-spin 0.8s linear infinite;
+        }
     </style>
 {% endblock %}