html,body{margin:0;height:100%;background:#000;color:#ddd;font-family:system-ui,sans-serif;overflow:hidden}
.full{position:absolute;inset:0;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:20px}
.hidden{display:none}
input{font-size:32px;padding:16px 24px;border-radius:12px;border:1px solid #555;background:#111;color:#fff;width:320px;text-align:center}
button{font-size:32px;padding:20px 48px;border-radius:16px;border:0;background:#e82127;color:#fff}
#info{position:absolute;left:12px;top:8px;font-size:18px;opacity:.8}
#msg,#err{font-size:22px}
#err{color:#f66}
canvas{display:block;width:100%;height:100%}