:root { color-scheme: light dark; }
body { margin: 0; font: 16px/1.6 -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif; }
main { max-width: 720px; margin: 0 auto; padding: 32px 16px; }
h1 { font-size: 28px; }
h2 { font-size: 20px; margin-top: 28px; }