body{font:18px system-ui;background:#111;color:#fff;margin:0}main{max-width:520px;margin:12vh auto;padding:32px}h1{font-size:48px}p{line-height:1.6}button{font:inherit;background:#fff;color:#111;border:0;padding:16px 24px;cursor:pointer}button:disabled{opacity:.5}