:root { color-scheme: light dark; }
body { font-family: system-ui, sans-serif; margin: 0; line-height: 1.6; }
header, main, footer { max-width: 42rem; margin: 0 auto; padding: 1rem 1.25rem; }
nav a { margin-right: 1rem; }
footer { color: #777; font-size: 0.9rem; }