body {margin:0;font-family:sans-serif;background:#f9f9f9;}
header {background:#378ae6;color:#fff;padding:16px;}
nav a {margin:0 10px;color:#fff;text-decoration:none;}
main {max-width:800px;margin:24px auto;padding:24px;background:#fff;border-radius:8px;}
footer {text-align:center;padding:16px;background:#378ae6;color:#fff;margin-top:24px;}