*{box-sizing:border-box}body{margin:0;padding:20px;background:#fff;color:#111;font:18px system-ui,sans-serif}.card{max-width:560px;margin:0 auto;padding:24px}label{display:block;font-weight:700;font-size:24px;margin:28px 0 12px}input{display:block;width:100%;height:88px;border:3px solid #111;border-radius:12px;text-align:center;font-size:52px;font-weight:800;letter-spacing:16px;background:#fff;color:#111}button{width:100%;height:64px;margin-top:20px;border:0;border-radius:12px;background:#111;color:#fff;font-size:24px;font-weight:700}.error{color:#b00020;font-weight:700}pre{white-space:pre-wrap;word-break:break-word;font-size:13px;color:#555}