:root { --w: 720px; }
* { box-sizing: border-box; }
body { font-family: system-ui, -apple-system, Segoe UI, Roboto, sans-serif; margin: 40px 20px; line-height: 1.6; }
.wrap { max-width: var(--w); margin: 0 auto; }
h1 { margin: 0 0 .3em; }
.btn { display:inline-block; padding:.7em 1.1em; border-radius:8px; text-decoration:none; border:1px solid #ccc; }