add problem content.

index.html

@@ -2,7 +2,7 @@
 <html lang="zh-Hans-CN">
   <head>
     <meta charset="UTF-8" />
-    <link rel="icon" type="image/svg+xml" href="/vite.svg" />
+    <link rel="shortcut icon" href="/public/website/favicon.ico">
     <meta name="viewport" content="width=device-width, initial-scale=1.0" />
     <title>OJ</title>
     <script>