:root{font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;color:#172b40;background:#fff}*{box-sizing:border-box}body{margin:0}main{max-width:500px;margin:auto;padding:clamp(28px,8vw,60px) 28px}small{letter-spacing:.16em;color:#54758c;font-size:11px}h1{font-size:42px;line-height:1.18;letter-spacing:-.04em;margin:26px 0}p,li{line-height:1.75;font-size:16px}ol{padding-left:22px;margin:28px 0}li{margin:10px 0}button{width:100%;border:0;border-radius:14px;padding:17px;background:#1d4ed8;color:white;font-size:17px;font-weight:600}button:disabled{opacity:.5}.hint{font-size:13px;color:#657785;margin-top:20px}#error{color:#b42318}#board{position:fixed;inset:0;width:100%;height:100dvh;background:white;touch-action:manipulation}#board[hidden],main[hidden]{display:none}