*{box-sizing:border-box}body{margin:0;font-family:system-ui,-apple-system,"PingFang SC","Microsoft YaHei",sans-serif;background:#0f172a;color:#e5e7eb;line-height:1.6}
header{max-width:820px;margin:0 auto;padding:24px 16px;text-align:center}
h1{font-size:32px;margin:0}h2{font-size:22px}
.warn{background:#fef3c7;color:#78350f;border-radius:12px;padding:12px;font-size:15px}
main{max-width:820px;margin:0 auto;padding:0 16px 32px}
.choice{display:flex;gap:12px;flex-wrap:wrap;justify-content:center;margin:16px 0}
.big{padding:14px 20px;font-size:19px;font-weight:800;border:0;border-radius:14px;background:#22c55e;color:#fff;cursor:pointer}
.big.alt{background:#38bdf8}.btn{background:#334155;color:#fff;border:0;padding:10px 16px;border-radius:10px;font-size:16px;cursor:pointer;margin-right:8px}
.pane{background:#1e293b;border-radius:18px;padding:20px;margin-top:16px}.hidden{display:none}
.code{font-size:64px;font-weight:900;letter-spacing:12px;text-align:center;background:#0f172a;border-radius:16px;padding:16px}
.status{font-size:18px;text-align:center}.hint{color:#94a3b8;font-size:15px}
input{width:100%;padding:12px;font-size:17px;border-radius:10px;border:2px solid #334155;background:#0f172a;color:#fff;margin:6px 0 14px}
video{width:100%;background:#000;border-radius:12px;min-height:200px}
.how{background:#1e293b;border-radius:18px;padding:20px;margin-top:20px}
footer{text-align:center;color:#64748b;padding:20px;font-size:14px}