:root { color-scheme: light dark; }
body { margin: 0; font: 16px/1.6 system-ui, -apple-system, "Segoe UI", sans-serif; }
main { max-width: 42rem; margin: 0 auto; padding: 2rem 1rem; }
h1 { font-size: 1.6rem; }
h2 { font-size: 1.15rem; margin-top: 1.8rem; }
footer, nav { margin-top: 2rem; }