.auth-section {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--space-10) var(--space-6);
    position: relative;
    overflow: hidden;
  }

  /* ═══ Animated Background ═══ */
  .auth-bg {
    position: absolute;
    inset: 0;
    pointer-events: none;
    z-index: 0;
  }

  .auth-orb {
    position: absolute;
    border-radius: 50%;
    filter: blur(100px);
    opacity: 0.35;
    animation: authOrbFloat 18s ease-in-out infinite;
  }

  .auth-orb-1 {
    width: 500px;
    height: 500px;
    background: linear-gradient(135deg, #6366f1, #8b5cf6);
    top: -180px;
    right: -120px;
  }

  .auth-orb-2 {
    width: 350px;
    height: 350px;
    background: linear-gradient(135deg, #3b82f6, #6366f1);
    bottom: -100px;
    left: -80px;
    animation-delay: -8s;
  }

  .auth-orb-3 {
    width: 250px;
    height: 250px;
    background: linear-gradient(135deg, #ec4899, #f43f5e);
    top: 40%;
    left: 60%;
    animation-delay: -4s;
    opacity: 0.15;
  }

  @keyframes authOrbFloat {
    0%, 100% { transform: translate(0, 0) scale(1); }
    33% { transform: translate(30px, -25px) scale(1.06); }
    66% { transform: translate(-15px, 15px) scale(0.94); }
  }

  .auth-grid-lines {
    position: absolute;
    inset: 0;
    background-image:
      linear-gradient(rgba(99, 102, 241, 0.04) 1px, transparent 1px),
      linear-gradient(90deg, rgba(99, 102, 241, 0.04) 1px, transparent 1px);
    background-size: 50px 50px;
    mask-image: radial-gradient(ellipse at center, black 0%, transparent 75%);
  }

  /* ═══ Container & Card ═══ */
  .auth-container {
    width: 100%;
    max-width: 520px;
    position: relative;
    z-index: 1;
  }

  .auth-card {
    padding: var(--space-10);
    background: rgba(255, 255, 255, 0.72);
    backdrop-filter: blur(24px) saturate(1.5);
    -webkit-backdrop-filter: blur(24px) saturate(1.5);
    border: 1px solid rgba(255, 255, 255, 0.6);
    border-radius: var(--radius-2xl);
    margin-bottom: var(--space-6);
    box-shadow:
      0 8px 32px rgba(0, 0, 0, 0.06),
      0 2px 8px rgba(0, 0, 0, 0.04),
      inset 0 1px 0 rgba(255, 255, 255, 0.8);
    animation: cardEntrance 0.6s cubic-bezier(0.16, 1, 0.3, 1) both;
  }

  html:not(.light-mode) .auth-card {
    background: rgba(15, 15, 25, 0.72);
    border-color: rgba(255, 255, 255, 0.08);
    box-shadow:
      0 8px 32px rgba(0, 0, 0, 0.3),
      0 2px 8px rgba(0, 0, 0, 0.2),
      inset 0 1px 0 rgba(255, 255, 255, 0.05);
  }

  @keyframes cardEntrance {
    from { opacity: 0; transform: translateY(24px) scale(0.97); }
    to { opacity: 1; transform: translateY(0) scale(1); }
  }

  /* ═══ Logo ═══ */
  .auth-logo {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-3);
    margin-bottom: var(--space-8);
    text-decoration: none;
  }

  .logo-mark { width: 40px; height: 40px; display: flex; align-items: center; justify-content: center; }
  .logo-mark svg { width: 32px; height: 36px; }
  .logo-text { display: flex; flex-direction: column; line-height: 1; gap: 1px; }
  .logo-traffic { font-size: 0.8rem; font-weight: 600; color: var(--text-primary); letter-spacing: 0.14em; text-transform: uppercase; }
  .logo-orchestrator { font-size: 0.8rem; font-weight: 500; background: linear-gradient(135deg, #6366f1, #8b5cf6); -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent; letter-spacing: 0.02em; }

  /* ═══ Title ═══ */
  .auth-title { font-size: var(--text-2xl); font-weight: var(--font-bold); text-align: center; margin-bottom: var(--space-2); color: var(--text-primary); }
  .auth-subtitle { text-align: center; color: var(--text-tertiary); margin-bottom: var(--space-8); }

  /* ═══ Plan Cards ═══ */
  .plan-card {
    display: flex; flex-direction: column; align-items: flex-start; gap: 0;
    padding: 12px 14px; background: rgba(255,255,255,0.04); border: 1.5px solid var(--border-subtle);
    border-radius: var(--radius-lg); cursor: pointer; transition: all 0.2s ease;
    font-family: inherit; color: var(--text-primary); text-align: left;
  }
  .plan-card:hover { border-color: rgba(99,102,241,0.35); background: rgba(99,102,241,0.04); transform: translateY(-1px); }
  .plan-card.selected { border-color: #6366f1; background: rgba(99,102,241,0.1); box-shadow: 0 0 0 1px rgba(99,102,241,0.3); }
  .plan-header { display: flex; flex-wrap: wrap; align-items: center; gap: 6px; width: 100%; margin-bottom: 6px; }
  .plan-name { font-size: var(--text-sm); font-weight: 600; }
  .plan-price { font-size: 12px; color: var(--text-tertiary); font-weight: 500; margin-left: auto; }
  .plan-badge { font-size: 9px; font-weight: 700; text-transform: uppercase; letter-spacing: 0.05em; background: linear-gradient(135deg, #6366f1, #8b5cf6); color: white; padding: 1px 6px; border-radius: 99px; line-height: 1.6; }
  .plan-card.selected .plan-price { color: #818cf8; }
  .plan-features { list-style: none; padding: 0; margin: 0; width: 100%; }
  .plan-features li {
    font-size: 11px; color: var(--text-tertiary); padding: 1.5px 0; padding-left: 14px; position: relative; line-height: 1.4;
  }
  .plan-features li::before { content: '✓'; position: absolute; left: 0; color: #22c55e; font-size: 10px; font-weight: 700; }
  .plan-card.selected .plan-features li { color: var(--text-secondary); }
  .compare-link {
    display: block; text-align: center; font-size: 12px; color: var(--brand-primary);
    text-decoration: none; margin-top: 8px; font-weight: 500;
  }
  .compare-link:hover { text-decoration: underline; }
  .light-mode .plan-card { background: rgba(0,0,0,0.02); }
  .light-mode .plan-card:hover { background: rgba(99,102,241,0.06); }
  .light-mode .plan-card.selected { background: rgba(99,102,241,0.08); }
  @media (max-width: 480px) {
    #planCards { grid-template-columns: 1fr !important; }
    .plan-header { flex-wrap: nowrap; }
  }

  /* ═══ OAuth Buttons ═══ */
  .oauth-buttons { display: flex; flex-direction: column; gap: var(--space-3); }

  .oauth-btn {
    display: flex; align-items: center; justify-content: center; gap: var(--space-3);
    width: 100%; padding: var(--space-3) var(--space-4);
    background: rgba(255, 255, 255, 0.55); border: 1px solid rgba(0, 0, 0, 0.06);
    border-radius: var(--radius-lg); font-size: var(--text-sm); font-weight: var(--font-medium);
    color: var(--text-primary); cursor: pointer;
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1); backdrop-filter: blur(8px);
  }

  html:not(.light-mode) .oauth-btn { background: rgba(255, 255, 255, 0.04); border-color: rgba(255, 255, 255, 0.08); }
  .oauth-btn:hover { background: rgba(255, 255, 255, 0.85); border-color: rgba(99, 102, 241, 0.3); transform: translateY(-1px); box-shadow: 0 4px 12px rgba(0, 0, 0, 0.06); }
  html:not(.light-mode) .oauth-btn:hover { background: rgba(255, 255, 255, 0.08); border-color: rgba(255, 255, 255, 0.15); }

  /* ═══ Divider ═══ */
  .divider { display: flex; align-items: center; gap: var(--space-4); margin: var(--space-6) 0; }
  .divider::before, .divider::after { content: ''; flex: 1; height: 1px; background: var(--border-subtle); }
  .divider span { font-size: var(--text-xs); color: var(--text-quaternary); text-transform: uppercase; letter-spacing: 0.05em; }

  /* ═══ Form ═══ */
  .form-row { display: grid; grid-template-columns: 1fr 1fr; gap: var(--space-4); }
  @media (max-width: 640px) { .form-row { grid-template-columns: 1fr; } }
  .form-group { margin-bottom: var(--space-5); }
  .form-group label { display: block; font-size: var(--text-sm); font-weight: var(--font-medium); color: var(--text-primary); margin-bottom: var(--space-2); }

  .form-group input[type="email"],
  .form-group input[type="password"],
  .form-group input[type="text"] {
    width: 100%; padding: var(--space-3) var(--space-4);
    background: rgba(255, 255, 255, 0.6); border: 1px solid rgba(0, 0, 0, 0.08);
    border-radius: var(--radius-lg); font-size: var(--text-base); color: var(--text-primary);
    transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1); backdrop-filter: blur(8px);
  }

  html:not(.light-mode) .form-group input[type="email"],
  html:not(.light-mode) .form-group input[type="password"],
  html:not(.light-mode) .form-group input[type="text"] {
    background: rgba(255, 255, 255, 0.05); border-color: rgba(255, 255, 255, 0.1);
  }

  .form-group input:focus { outline: none; border-color: var(--brand-primary); box-shadow: 0 0 0 4px rgba(99, 102, 241, 0.12), 0 1px 3px rgba(0, 0, 0, 0.06); transform: translateY(-1px); }
  .form-group input::placeholder { color: var(--text-quaternary); }

  .password-wrapper { position: relative; }
  .password-wrapper input { padding-right: var(--space-10) !important; }
  .password-toggle {
    position: absolute; right: 12px; top: 50%; transform: translateY(-50%);
    background: none; border: none; padding: 4px; color: var(--text-tertiary);
    cursor: pointer; display: flex; align-items: center; justify-content: center;
    transition: color 0.2s;
  }
  .password-toggle:hover { color: var(--text-primary); }

  /* Password Strength */
  .password-strength { height: 3px; margin-top: var(--space-2); border-radius: var(--radius-full); background: var(--surface-3); overflow: hidden; }
  .password-strength::before { content: ''; display: block; height: 100%; width: var(--strength, 0%); background: var(--strength-color, var(--error)); transition: all var(--duration-fast); }

  /* ═══ Checkbox ═══ */
  .checkbox-group { margin-top: var(--space-2); }
  .checkbox-label { display: flex; align-items: flex-start; gap: var(--space-3); font-size: var(--text-sm); color: var(--text-secondary); cursor: pointer; line-height: 1.4; }
  .checkbox-label input { display: none; }
  .checkbox-label a { color: var(--brand-primary); text-decoration: none; }
  .checkbox-label a:hover { text-decoration: underline; }
  .checkmark { width: 18px; height: 18px; flex-shrink: 0; margin-top: 1px; border: 2px solid var(--border-default); border-radius: var(--radius-sm); display: flex; align-items: center; justify-content: center; transition: all var(--duration-fast); }
  .checkbox-label input:checked + .checkmark { background: var(--brand-primary); border-color: var(--brand-primary); }
  .checkbox-label input:checked + .checkmark::after { content: '✓'; color: white; font-size: 12px; }

  /* ═══ Footer & Benefits ═══ */
  .auth-footer { text-align: center; font-size: var(--text-sm); color: var(--text-tertiary); margin-top: var(--space-6); }
  .auth-footer a { color: var(--brand-primary); text-decoration: none; font-weight: var(--font-medium); }
  .auth-footer a:hover { text-decoration: underline; }

  /* Trust line */
  .signup-trust-line {
    font-size: var(--text-xs);
    color: var(--text-tertiary);
    text-align: center;
    margin-top: var(--space-4);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-2);
    flex-wrap: wrap;
  }
  .trust-check { color: #22c55e; font-weight: 700; font-size: 12px; }
  .trust-sep { color: var(--border-subtle); margin: 0 2px; }

  /* Trial auto-charge disclosure */
  .trial-disclosure {
    margin-top: var(--space-4);
    padding: var(--space-4);
    background: rgba(251, 191, 36, 0.08);
    border: 1px solid rgba(251, 191, 36, 0.25);
    border-radius: var(--radius-lg);
    animation: disclosureFade 0.3s ease-out;
  }
  html:not(.light-mode) .trial-disclosure {
    background: rgba(251, 191, 36, 0.06);
    border-color: rgba(251, 191, 36, 0.2);
  }
  .trial-disclosure-text {
    font-size: 12px;
    line-height: 1.5;
    color: var(--text-secondary);
    margin: 0;
  }
  .trial-disclosure-text strong { color: var(--text-primary); }
  .trial-disclosure-text a { color: var(--brand-primary); text-decoration: none; }
  .trial-disclosure-text a:hover { text-decoration: underline; }
  @keyframes disclosureFade {
    from { opacity: 0; transform: translateY(-4px); }
    to { opacity: 1; transform: translateY(0); }
  }

  .benefits { display: flex; justify-content: center; gap: var(--space-6); flex-wrap: wrap; }
  .benefit-item { display: flex; align-items: center; gap: var(--space-2); font-size: var(--text-sm); color: var(--text-secondary); }
  .benefit-item svg { color: var(--success); }

  /* ═══ Social Proof Bar ═══ */
  .signup-social-proof {
    text-align: center;
    padding: var(--space-6) var(--space-4);
    background: rgba(255, 255, 255, 0.45);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid rgba(255, 255, 255, 0.4);
    border-radius: var(--radius-xl);
    animation: cardEntrance 0.6s cubic-bezier(0.16, 1, 0.3, 1) 0.15s both;
  }
  html:not(.light-mode) .signup-social-proof {
    background: rgba(15, 15, 25, 0.5);
    border-color: rgba(255, 255, 255, 0.06);
  }
  .proof-stats {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-4);
    flex-wrap: wrap;
  }
  .proof-stat { display: flex; flex-direction: column; align-items: center; gap: 2px; }
  .proof-value {
    font-size: var(--text-lg);
    font-weight: var(--font-bold);
    background: linear-gradient(135deg, #6366f1, #8b5cf6);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
  }
  .proof-label { font-size: var(--text-xs); color: var(--text-tertiary); text-transform: uppercase; letter-spacing: 0.05em; }
  .proof-divider { width: 1px; height: 28px; background: var(--border-subtle); flex-shrink: 0; }
  .proof-note { font-size: var(--text-xs); color: var(--text-quaternary); margin-top: var(--space-3); }
  @media (max-width: 480px) {
    .proof-stats { gap: var(--space-3); }
    .proof-divider { display: none; }
    .proof-stats { justify-content: space-around; }
  }

  /* ═══ Error States ═══ */
  .form-error-banner { padding: var(--space-3) var(--space-4); background: var(--error-muted); border: 1px solid rgba(239, 68, 68, 0.3); border-radius: var(--radius-lg); color: var(--error); font-size: var(--text-sm); margin-bottom: var(--space-5); display: flex; align-items: center; gap: var(--space-2); }
  .form-error-banner::before { content: '⚠'; }
  .form-group input.input-error { border-color: var(--error); }
  .form-group input.input-error:focus { box-shadow: 0 0 0 3px rgba(239, 68, 68, 0.1); }
  .field-error { margin-top: var(--space-2); font-size: var(--text-sm); color: var(--error); }
  .field-hint { margin-top: var(--space-2); font-size: var(--text-xs); color: var(--text-quaternary); }
  .label-required::after { content: ' *'; color: var(--error); }

  /* ═══ Button Loading ═══ */
  .btn .btn-spinner { width: 16px; height: 16px; border: 2px solid rgba(255, 255, 255, 0.3); border-top-color: white; border-radius: 50%; animation: spin 0.8s linear infinite; }
  @keyframes spin { to { transform: rotate(360deg); } }

  /* ═══ Reduced Motion ═══ */
  @media (prefers-reduced-motion: reduce) {
    .auth-orb { animation: none; }
    .auth-card { animation: none; }
  }