<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
<title>Hello, world!</title>
<meta name="description" content="A simple HTML document.">
</head>
<body>
<h1>Hello, world!</h1>
<p>This demonstrates a simple HTML document.</p>
</body>
</html>