html{color-scheme:light dark}body{font:17px/1.65 system-ui,-apple-system,sans-serif;margin:0;background:Canvas;color:CanvasText}main{max-width:720px;margin:0 auto;padding:32px 24px}h1{font-size:30px;line-height:1.2}h2{font-size:21px;margin-top:32px}.brand{font-weight:700;color:#4788ed}a{color:#4788ed}#challenge{margin:28px 0}