/* ── Auth Screen ── */
    #auth-screen {
      display: flex;
      align-items: center;
      justify-content: center;
      min-height: 100vh;
      background:
        radial-gradient(ellipse 80% 60% at 50% -20%, rgba(99, 102, 241, .25), transparent),
        var(--bg);
    }

    .auth-card {
      background: var(--card);
      border: 1px solid var(--border);
      border-radius: 20px;
      padding: 48px 40px;
      width: 100%;
      max-width: 420px;
      box-shadow: var(--shadow);
    }

    .auth-logo {
      display: flex;
      align-items: center;
      gap: 12px;
      margin-bottom: 32px;
    }

    .auth-logo .icon {
      width: 44px;
      height: 44px;
      background: linear-gradient(135deg, var(--primary), #818cf8);
      border-radius: 12px;
      display: grid;
      place-items: center;
      font-size: 22px;
    }

    .auth-logo h1 {
      font-size: 18px;
      font-weight: 700;
    }

    .auth-logo p {
      font-size: 12px;
      color: var(--text-dim);
    }

    .auth-title {
      font-size: 22px;
      font-weight: 700;
      margin-bottom: 8px;
    }

    .auth-sub {
      font-size: 14px;
      color: var(--text-dim);
      margin-bottom: 28px;
    }

    /* ── Form elements ── */
    .field {
      margin-bottom: 18px;
    }

    .field label {
      display: block;
      font-size: 13px;
      font-weight: 500;
      margin-bottom: 6px;
      color: var(--text-dim);
    }

    .field label .req {
      color: var(--primary);
    }

    .field input,
    .field select {
      width: 100%;
      background: var(--surface);
      border: 1px solid var(--border);
      border-radius: 10px;
      padding: 11px 14px;
      color: var(--text);
      font-size: 14px;
      font-family: inherit;
      outline: none;
      transition: border .2s;
    }

    .field input:focus,
    .field select:focus {
      border-color: var(--primary);
    }

    .field .hint {
      font-size: 11px;
      color: var(--muted);
      margin-top: 5px;
    }

    /* ── Buttons ── */
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      padding: 10px 18px;
      border-radius: 10px;
      font-size: 14px;
      font-weight: 600;
      border: none;
      cursor: pointer;
      transition: all .2s;
      font-family: inherit;
      text-decoration: none;
      white-space: nowrap;
    }

    .btn-primary {
      background: var(--primary);
      color: #fff;
      width: 100%;
      padding: 13px;
    }

    .btn-primary:hover:not(:disabled) {
      background: var(--primary-h);
      transform: translateY(-1px);
    }

    .btn-sm {
      padding: 6px 12px;
      font-size: 12px;
      border-radius: 8px;
    }

    .btn-success {
      background: rgba(34, 197, 94, .15);
      color: var(--success);
      border: 1px solid rgba(34, 197, 94, .3);
    }

    .btn-danger {
      background: rgba(239, 68, 68, .12);
      color: var(--danger);
      border: 1px solid rgba(239, 68, 68, .25);
    }

    .btn-warn {
      background: rgba(245, 158, 11, .12);
      color: var(--warn);
      border: 1px solid rgba(245, 158, 11, .25);
    }

    .btn-ghost {
      background: rgba(255, 255, 255, .05);
      color: var(--text-dim);
      border: 1px solid var(--border);
    }

    .btn:disabled {
      opacity: .5;
      cursor: not-allowed;
    }

    .btn-primary:disabled {
      transform: none;
    }

    /* Nút Google — official style */
    .btn-google {
      display: inline-flex;
      align-items: center;
      gap: 10px;
      background: #fff;
      color: #3c4043;
      font-size: 15px;
      font-weight: 600;
      padding: 11px 24px;
      border: 1px solid #dadce0;
      border-radius: 10px;
      cursor: pointer;
      transition: all .2s;
      font-family: inherit;
      box-shadow: 0 1px 3px rgba(0, 0, 0, .15);
    }

    .btn-google:hover:not(:disabled) {
      background: #f8f9fa;
      box-shadow: 0 2px 8px rgba(0, 0, 0, .2);
      transform: translateY(-1px);
    }

    .btn-google:disabled {
      opacity: .6;
      cursor: not-allowed;
      transform: none;
    }

    /* ── Modal (Mới) ── */
    #combo-modal.modal {
      display: none;
      position: fixed;
      inset: 0;
      background: rgba(0, 0, 0, 0.6);
      z-index: 1000;
      align-items: center;
      justify-content: center;
      backdrop-filter: blur(4px);
      animation: fadeIn 0.15s ease-out;
    }

    .modal-content {
      background: var(--surface);
      padding: 24px;
      border-radius: 12px;
      width: 100%;
      max-width: 500px;
      border: 1px solid var(--border);
      box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
      animation: slideUp 0.2s ease-out;
      max-height: 85vh;
      display: flex;
      flex-direction: column;
    }

    .modal-header {
      font-size: 18px;
      font-weight: 600;
      margin-bottom: 16px;
      color: var(--text);
    }

    .modal-body {
      flex: 1;
      overflow-y: auto;
      margin-bottom: 20px;
      padding-right: 4px;
    }

    .modal-body::-webkit-scrollbar {
      width: 6px;
    }

    .modal-body::-webkit-scrollbar-thumb {
      background: var(--border);
      border-radius: 4px;
    }

    .modal-footer {
      display: flex;
      justify-content: flex-end;
      gap: 12px;
      border-top: 1px solid var(--border);
      padding-top: 16px;
    }

    @keyframes fadeIn {
      from {
        opacity: 0;
      }

      to {
        opacity: 1;
      }
    }

    @keyframes slideUp {
      from {
        transform: translateY(20px);
        opacity: 0;
      }

      to {
        transform: translateY(0);
        opacity: 1;
      }
    }

    /* Auth type badges */
    .google-badge {
      background: rgba(66, 133, 244, .12);
      color: #4285F4;
      border: 1px solid rgba(66, 133, 244, .3);
      font-size: 11px;
      padding: 3px 9px;
      border-radius: 100px;
      font-weight: 600;
    }

    .pw-badge {
      background: rgba(99, 102, 241, .12);
      color: var(--primary);
      border: 1px solid rgba(99, 102, 241, .3);
      font-size: 11px;
      padding: 3px 9px;
      border-radius: 100px;
      font-weight: 600;
    }


    /* ── Alert ── */
    .alert {
      padding: 10px 14px;
      border-radius: 8px;
      font-size: 13px;
      margin-bottom: 16px;
      display: none;
    }

    .alert.error {
      background: rgba(239, 68, 68, .12);
      border: 1px solid rgba(239, 68, 68, .3);
      color: #fca5a5;
    }

    .alert.success {
      background: rgba(34, 197, 94, .1);
      border: 1px solid rgba(34, 197, 94, .3);
      color: #86efac;
    }

    .alert.show {
      display: block;
    }