body { font-family: sans-serif; background: #fff; color: #111; }
header { background: green; color: white; padding: 1em; text-align: center; }
nav a { color: white; margin: 0 1em; text-decoration: none; }
footer { background: #222; color: white; padding: 1em; text-align: center; }
main { padding: 2em; }