:root { --primary: #6366f1; }
* { box-sizing: border-box; }
body { margin: 0; font-family: system-ui, sans-serif; line-height: 1.6; }
main { max-width: 720px; margin: 4rem auto; padding: 0 1rem; }
h1 { color: var(--primary); }
code { background: #f4f4f5; padding: 0.1rem 0.3rem; border-radius: 4px; }