body { font-family: Arial, sans-serif; margin: 0; padding: 0; }
header nav { background: #333; padding: 1em; }
header nav a { color: #fff; margin: 0 1em; text-decoration: none; }
main { padding: 2em; }
footer { background: #f1f1f1; padding: 1em; text-align: center; }