/* ── Auth / Login screens ─────────────────────────────── */
    .auth-screen {
      display: none;
      position: fixed;
      inset: 0;
      background: linear-gradient(135deg, #2c3e50 0%, #3498db 100%);
      z-index: 9000;
      align-items: center;
      justify-content: center;
    }
    .auth-screen.active { display: flex; }

    .auth-card {
      background: var(--clr-white);
      border-radius: 12px;
      box-shadow: 0 16px 48px rgba(0,0,0,.3);
      width: 400px;
      max-width: 92vw;
      padding: 40px 36px;
    }

    .auth-logo {
      display: flex;
      align-items: center;
      gap: 10px;
      justify-content: center;
      margin-bottom: 28px;
    }
    .auth-logo svg { width: 36px; height: 36px; color: var(--clr-primary); }
    .auth-logo h1 { font-size: 1.5rem; font-weight: 700; color: var(--clr-dark); }

    .auth-title {
      font-size: 1.1rem;
      font-weight: 700;
      color: var(--clr-dark);
      margin-bottom: 6px;
      text-align: center;
    }
    .auth-subtitle {
      font-size: .85rem;
      color: #7f8c8d;
      text-align: center;
      margin-bottom: 24px;
    }

    .auth-form-group {
      margin-bottom: 16px;
    }
    .auth-form-group label {
      display: block;
      font-size: .8rem;
      font-weight: 600;
      color: #636e72;
      margin-bottom: 6px;
      text-transform: uppercase;
      letter-spacing: .4px;
    }
    .auth-form-group input {
      width: 100%;
      padding: 10px 14px;
      border: 1.5px solid #dcdde1;
      border-radius: var(--radius);
      font-size: .95rem;
      outline: none;
      transition: border-color .15s;
    }
    .auth-form-group input:focus { border-color: var(--clr-primary); }

    .auth-btn {
      width: 100%;
      padding: 11px;
      border: none;
      border-radius: var(--radius);
      background: var(--clr-primary);
      color: var(--clr-white);
      font-size: 1rem;
      font-weight: 700;
      cursor: pointer;
      margin-top: 8px;
      transition: background .15s;
    }
    .auth-btn:hover { background: var(--clr-primary-d); }
    .auth-btn:disabled { opacity: .6; cursor: not-allowed; }

    .auth-btn-secondary {
      width: 100%;
      padding: 10px;
      background: transparent;
      color: var(--clr-primary);
      border: 1px solid var(--clr-primary);
      border-radius: var(--radius);
      font-size: .9rem;
      font-weight: 600;
      cursor: pointer;
      transition: background .15s, color .15s;
    }
    .auth-btn-secondary:hover { background: var(--clr-primary); color: var(--clr-white); }
    .auth-btn-secondary:disabled { opacity: .5; cursor: not-allowed; }

    .auth-backup-section { margin-top: 18px; }
    .auth-backup-separator {
      display: flex; align-items: center; gap: 8px;
      color: #95a5a6; font-size: .78rem; text-transform: uppercase;
      letter-spacing: .5px; margin: 14px 0 10px;
    }
    .auth-backup-separator::before,
    .auth-backup-separator::after {
      content: ''; flex: 1; height: 1px; background: #dcdde1;
    }

    .auth-error {
      background: rgba(231,76,60,.1);
      border: 1px solid rgba(231,76,60,.3);
      border-radius: var(--radius);
      color: var(--clr-danger);
      padding: 10px 14px;
      font-size: .88rem;
      margin-bottom: 14px;
      display: none;
    }
    .auth-error.visible { display: block; }

    .auth-info {
      background: rgba(52,152,219,.08);
      border: 1px solid rgba(52,152,219,.2);
      border-radius: var(--radius);
      color: var(--clr-dark);
      padding: 12px 14px;
      font-size: .85rem;
      margin-bottom: 16px;
      line-height: 1.6;
    }
    .auth-secret {
      font-family: monospace;
      font-size: 1rem;
      font-weight: 700;
      letter-spacing: 2px;
      background: var(--clr-light);
      padding: 8px 12px;
      border-radius: var(--radius);
      text-align: center;
      margin: 8px 0;
      word-break: break-all;
    }
    .auth-uri-row {
      display: flex;
      gap: 8px;
      margin-top: 8px;
    }
    .auth-uri-row input {
      flex: 1;
      font-family: monospace;
      font-size: .72rem;
      padding: 6px 8px;
      border: 1px solid #dcdde1;
      border-radius: var(--radius);
      outline: none;
      color: #636e72;
    }
    .auth-uri-row button {
      padding: 6px 12px;
      border: 1px solid #dcdde1;
      border-radius: var(--radius);
      background: var(--clr-light);
      color: var(--clr-dark);
      font-size: .8rem;
      font-weight: 600;
      cursor: pointer;
      white-space: nowrap;
    }
    .auth-uri-row button:hover { background: #dfe6e9; }