<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1" />
<title>Hello World</title>
<style>
html, body { height: 100%; margin: 0; font: 16px/1.5 system-ui, sans-serif; }
.wrap { display:flex; align-items:center; justify-content:center; height:100%; }
.card { padding: 2rem 2.5rem; border: 1px solid #e5e7eb; border-radius: 12px; box-shadow: 0 8px 20px rgba(0,0,0,.06); }
h1 { margin: 0; font-size: 2rem; }
</style>
</head>
<body>
<div class="wrap">
<div class="card">
<h1>Hello World</h1>
</div>
</div>
</body>
</html>