修复监控视频展示并更新产品素材

frontend/src/components/hlsPlayer/index.module.less

@@ -1,5 +1,7 @@
 .player {
-  // hide the timeline
+  display: block;
+  background: #020617;
+
   &::-webkit-media-controls-timeline {
     display: none;
   }

frontend/src/pages/aiChat/index.tsx

@@ -482,4 +482,4 @@ const AiChat: FC = () => {
   );
 };
 
-export default AiChat;
+export default AiChat;

frontend/src/pages/monitScreen/index.module.less

@@ -1,7 +1,11 @@
 .content {
   padding: 8px;
 }
+
 .video {
+  display: block;
   width: 100%;
   height: 320px;
+  object-fit: cover;
+  background: #020617;
 }