*{box-sizing:border-box}body{margin:0;font:16px system-ui;background:#f4f6fb;color:#172033}main{max-width:640px;margin:auto;padding:24px}button{display:block;margin:20px 0;padding:14px 20px;border:0;border-radius:14px;background:#2463eb;color:#fff}output{font-size:36px}input,textarea{width:100%;margin-bottom:10px;padding:8px;border:1px solid #ccc;border-radius:4px}@media(max-width:600px){main{padding:12px}button{width:100%}}