<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Html文档</title>
</head>
<body>
<div>
<h1>我是一级标题</h1>
<h2>我是二级标题</h2>
</div>
</body>
</html>