1<!DOCTYPE html>
2<html lang="en">
3<head>
4 <meta charset="UTF-8">
5 <meta name="viewport" content="width=device-width, initial-scale=1.0">
6 <title>Code Display Example</title>
7</head>
8<body>
9 <h1>Code Display Example</h1>
10 <pre>
11 <code class="html">
12 <span class="line-number">1<!DOCTYPE html>
13 </code>
14 </pre>
15</body>
16</html>