*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

  :root {
    --bg: #0a0a0a;
    --surface: #141414;
    --border: #252525;
    --text: #e8e8e8;
    --muted: #666;
    --accent: #e8590c;
    --accent-hover: #f76707;
    --danger: #e03131;
  }

  html, body { height: 100%; }
  body {
    font-family: -apple-system, 'Segoe UI', system-ui, sans-serif;
    background: var(--bg);
    color: var(--text);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 24px 16px;
  }

  body::before {
    content: '';
    position: fixed;
    top: 0; left: 0; right: 0;
    height: 3px;
    background: var(--accent);
    z-index: 100;
  }

  main { width: 100%; max-width: 380px; }

  /* ---- Brand ---- */
  .brand {
    display: flex;
    align-items: center;
    gap: 14px;
    margin: 0 0 24px 2px;
  }

  .eq-icon { display: flex; align-items: flex-end; gap: 3px; height: 22px; }
  .eq-icon span {
    display: block;
    width: 3px;
    background: var(--accent);
    animation: eq 1.4s ease-in-out infinite;
    transform-origin: bottom;
  }
  .eq-icon span:nth-child(1) { height: 35%; animation-delay: 0s; }
  .eq-icon span:nth-child(2) { height: 75%; animation-delay: .15s; }
  .eq-icon span:nth-child(3) { height: 50%; animation-delay: .35s; }
  .eq-icon span:nth-child(4) { height: 90%; animation-delay: .1s; }
  .eq-icon span:nth-child(5) { height: 60%; animation-delay: .25s; }

  @keyframes eq {
    0%, 100% { transform: scaleY(1); }
    50% { transform: scaleY(.3); }
  }

  .brand h1 {
    font-size: .85rem;
    font-weight: 700;
    letter-spacing: .14em;
    text-transform: uppercase;
  }
  .brand p {
    font-size: .72rem;
    color: var(--muted);
    margin-top: 3px;
    text-transform: uppercase;
    letter-spacing: .08em;
  }

  /* ---- Card ---- */
  .card {
    background: var(--surface);
    border: 1px solid var(--border);
    padding: 28px 24px;
    position: relative;
    overflow: hidden;
  }

  .step { display: none; }
  .step.active { display: block; animation: rise .25s ease-out; }
  @keyframes rise {
    from { opacity: 0; transform: translateY(8px); }
    to { opacity: 1; transform: none; }
  }

  label {
    display: block;
    font-size: .6rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: .14em;
    color: var(--muted);
    margin: 18px 0 7px;
  }
  label:first-of-type { margin-top: 0; }

  input {
    width: 100%;
    background: var(--bg);
    color: var(--text);
    border: 1px solid var(--border);
    padding: 11px 12px;
    font-size: .92rem;
    font-family: inherit;
    transition: border-color .15s;
  }
  input::placeholder { color: #3e3e3e; }
  input:focus {
    outline: none;
    border-color: var(--accent);
  }

  .code-input {
    letter-spacing: .5em;
    text-align: center;
    font-size: 1.4rem;
    font-variant-numeric: tabular-nums;
    padding-left: .5em;
  }

  button.primary {
    width: 100%;
    margin-top: 22px;
    border: 1px solid var(--accent);
    background: var(--accent);
    color: #fff;
    padding: 12px 14px;
    font-size: .72rem;
    font-weight: 700;
    font-family: inherit;
    text-transform: uppercase;
    letter-spacing: .1em;
    cursor: pointer;
    transition: background .12s, border-color .12s;
  }
  button.primary:hover { background: var(--accent-hover); border-color: var(--accent-hover); }
  button.primary:disabled { opacity: .4; cursor: default; }

  .back {
    background: none;
    border: 0;
    color: var(--muted);
    cursor: pointer;
    font-size: .75rem;
    font-family: inherit;
    padding: 4px 0;
    margin-bottom: 6px;
    display: inline-flex;
    align-items: center;
    gap: 6px;
    letter-spacing: .04em;
  }
  .back:hover { color: var(--text); }
  .back svg { width: 14px; height: 14px; }

  .step-title {
    font-size: .95rem;
    font-weight: 600;
    margin: 2px 0 4px;
  }
  .step-hint {
    font-size: .78rem;
    color: var(--muted);
    line-height: 1.5;
    margin-bottom: 4px;
  }

  #status {
    font-size: .75rem;
    color: var(--danger);
    min-height: 1.1em;
    margin-top: 14px;
  }