.auth-modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(17, 17, 17, 0.85);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 9999;
    padding: 1rem;
    backdrop-filter: blur(4px);
    opacity: 0;
    transition: opacity 0.3s ease;
  }
  .auth-modal-overlay.is-visible {
    opacity: 1;
  }
  .auth-modal-card {
    background: #ffffff;
    width: 100%;
    max-width: 480px;
    border-radius: 8px;
    padding: 2rem;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.2);
    border: 1px solid #e2e2dc;
    max-height: 90vh;
    overflow-y: auto;
    font-family: inherit;
    opacity: 0;
    transform: translateY(24px);
    transition: opacity 0.4s cubic-bezier(0.16, 1, 0.3, 1),
      transform 0.4s cubic-bezier(0.16, 1, 0.3, 1);
  }
  .auth-modal-overlay.is-visible .auth-modal-card {
    opacity: 1;
    transform: translateY(0);
  }
  .auth-modal-card h3 {
    font-size: 1.4rem;
    font-weight: 900;
    text-transform: uppercase;
    margin-bottom: 0.4rem;
    color: #111;
  }
  .auth-modal-card p {
    font-size: 0.9rem;
    color: #666;
    margin-bottom: 1.2rem;
  }

  .auth-alert {
    display: none;
    padding: 0.75rem 1rem;
    border-radius: 6px;
    font-size: 0.85rem;
    font-weight: 600;
    margin-bottom: 1.2rem;
    align-items: center;
    gap: 0.5rem;
    animation: fadeIn 0.2s ease-in-out;
  }
  .auth-alert.error {
    background: #fef2f2;
    color: #991b1b;
    border: 1px solid #fca5a5;
    display: flex;
  }
  .auth-alert.success {
    background: #f0fdf4;
    color: #166534;
    border: 1px solid #86efac;
    display: flex;
  }

  @keyframes fadeIn {
    from {
      opacity: 0;
      transform: translateY(-4px);
    }
    to {
      opacity: 1;
      transform: translateY(0);
    }
  }

  .auth-form-group {
    margin-bottom: 1rem;
  }
  .auth-form-group label {
    display: block;
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    margin-bottom: 0.3rem;
    color: #111;
  }
  .auth-form-group input,
  .auth-form-group select {
    width: 100%;
    padding: 0.7rem;
    border: 1px solid #ccc;
    border-radius: 6px;
    font-size: 0.9rem;
    outline: none;
    transition: border-color 0.2s;
  }
  .auth-form-group input:focus,
  .auth-form-group select:focus {
    border-color: #1d4ed8;
  }
  .auth-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.75rem;
  }

  /* Data Privacy Act consent */
  .auth-checkbox-row {
    display: flex;
    align-items: flex-start;
    gap: 0.6rem;
    margin-top: 1.2rem;
    padding-top: 1rem;
    border-top: 1px solid #eee;
  }
  .auth-checkbox-row input[type="checkbox"] {
    margin-top: 3px;
    width: 16px;
    height: 16px;
    flex-shrink: 0;
    accent-color: #1d4ed8;
    cursor: pointer;
  }
  .auth-checkbox-row label {
    font-size: 0.78rem;
    color: #444;
    line-height: 1.45;
    cursor: pointer;
  }
  .auth-checkbox-row label strong {
    color: #111;
  }

  /* Submit Button with Loading Animation */
  .auth-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 100%;
    background: #1d4ed8;
    color: #fff;
    border: none;
    padding: 0.75rem;
    border-radius: 6px;
    font-weight: 800;
    text-transform: uppercase;
    font-size: 0.85rem;
    cursor: pointer;
    margin-top: 1.2rem;
    transition: background 0.2s;
    position: relative;
  }
  .auth-btn:hover {
    background: #1e3a8a;
  }
  .auth-btn:disabled {
    background: #93c5fd;
    cursor: not-allowed;
  }

  /* Spinner Animation */
  .spinner {
    width: 16px;
    height: 16px;
    border: 2px solid #ffffff;
    border-top-color: transparent;
    border-radius: 50%;
    animation: spin 0.6s linear infinite;
    display: none;
    margin-left: 8px;
  }
  @keyframes spin {
    to {
      transform: rotate(360deg);
    }
  }
  .loading .spinner {
    display: inline-block;
  }
  .loading .btn-text {
    opacity: 0.8;
  }

  .hidden {
    display: none !important;
  }