:root { font-family: system-ui, sans-serif; }
main { max-width: 720px; margin: 4rem auto; line-height: 1.5; }
h1 { margin-bottom: .5rem;}
button { padding: .5rem .8rem; border: 1px solid #ccc; border-radius: .5rem; cursor: pointer; }
pre { background: #f7f7f7; padding: 1rem; border-radius: .5rem; }