:root { color-scheme: light dark; }
body { margin: 0; min-height: 100vh; display: grid; place-items: center;
       font: 16px/1.6 system-ui, -apple-system, "Segoe UI", sans-serif; }
main { padding: 24px; max-width: 60ch; }
h1 { font-size: 24px; letter-spacing: -.02em; margin: 0 0 8px; }