body{font-family:Arial,sans-serif;margin:0;background:#f4f4f4}header{background:#222;color:#fff;padding:20px}nav a{margin-right:15px}main{display:grid;grid-template-columns:3fr 1fr;gap:20px;padding:20px}article,aside{background:#fff;padding:20px;border-radius:8px}footer{text-align:center;padding:20px;background:#222;color:#fff}