/* ═══════════════════════════════════════════════════════════════════
   AUTH.CSS - Premium Dark Authentication Experience
   "Data Constellation" Design System
   ═══════════════════════════════════════════════════════════════════ */

/* ═══════════════════════════════════════════════════════════════════
   1. CSS CUSTOM PROPERTIES (DESIGN TOKENS)
   ═══════════════════════════════════════════════════════════════════ */
:root {
  /* Brand Colors */
  --auth-primary: #7e67fe;
  --auth-primary-rgb: 126, 103, 254;
  --auth-primary-light: #9d8bff;
  --auth-primary-dark: #6550e0;
  --auth-primary-glow: rgba(126, 103, 254, 0.4);

  /* Dark Surface Palette */
  --auth-surface-base: #0a0a0f;
  --auth-surface-card: #12121a;
  --auth-surface-elevated: #1a1a25;
  --auth-surface-input: #0f0f16;
  --auth-surface-hover: #1f1f2e;

  /* Text Hierarchy */
  --auth-text-primary: #f4f4f7;
  --auth-text-secondary: #a0a0b0;
  --auth-text-tertiary: #6b6b7b;
  --auth-text-muted: #45455a;

  /* Border & Dividers */
  --auth-border-default: rgba(255, 255, 255, 0.08);
  --auth-border-emphasis: rgba(255, 255, 255, 0.12);
  --auth-border-focus: rgba(126, 103, 254, 0.5);

  /* Status Colors */
  --auth-success: #10b981;
  --auth-success-rgb: 16, 185, 129;
  --auth-error: #ef4444;
  --auth-error-rgb: 239, 68, 68;
  --auth-warning: #f59e0b;
  --auth-info: #3b82f6;

  /* Typography */
  --auth-font-display: 'Sora', -apple-system, BlinkMacSystemFont, sans-serif;
  --auth-font-body: 'DM Sans', -apple-system, BlinkMacSystemFont, sans-serif;

  /* Spacing */
  --auth-space-xs: 0.25rem;
  --auth-space-sm: 0.5rem;
  --auth-space-md: 1rem;
  --auth-space-lg: 1.5rem;
  --auth-space-xl: 2rem;
  --auth-space-2xl: 3rem;
  --auth-space-3xl: 4rem;

  /* Border Radius */
  --auth-radius-sm: 0.5rem;
  --auth-radius-md: 0.75rem;
  --auth-radius-lg: 1rem;
  --auth-radius-xl: 1.5rem;

  /* Shadows */
  --auth-shadow-glow: 0 0 60px rgba(126, 103, 254, 0.15);
  --auth-shadow-card: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
  --auth-shadow-input: 0 2px 8px rgba(0, 0, 0, 0.3);

  /* Transitions */
  --auth-transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --auth-transition-normal: 250ms cubic-bezier(0.4, 0, 0.2, 1);
  --auth-transition-slow: 400ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* ═══════════════════════════════════════════════════════════════════
   2. BASE RESETS & GLOBAL STYLES
   ═══════════════════════════════════════════════════════════════════ */
*, *::before, *::after {
  box-sizing: border-box;
}

html, body {
  margin: 0;
  padding: 0;
  height: 100%;
}

body {
  font-family: var(--auth-font-body);
  font-size: 1rem;
  line-height: 1.6;
  color: var(--auth-text-primary);
  background: var(--auth-surface-base);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ═══════════════════════════════════════════════════════════════════
   3. LAYOUT - SPLIT SCREEN CONTAINER
   ═══════════════════════════════════════════════════════════════════ */
.auth-container {
  display: flex;
  min-height: 100vh;
  background: var(--auth-surface-base);
}

/* Left Panel - Visual Showcase */
.auth-visual-panel {
  display: none;
  position: relative;
  flex: 1;
  background: linear-gradient(135deg, #0a0a0f 0%, #12121a 100%);
  overflow: hidden;
}

/* Animated Grid Background */
.auth-visual-panel::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(126, 103, 254, 0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(126, 103, 254, 0.03) 1px, transparent 1px);
  background-size: 60px 60px;
  -webkit-mask-image: radial-gradient(ellipse 80% 80% at 50% 50%, black 40%, transparent 100%);
          mask-image: radial-gradient(ellipse 80% 80% at 50% 50%, black 40%, transparent 100%);
  animation: gridPulse 8s ease-in-out infinite;
}

@keyframes gridPulse {
  0%, 100% { opacity: 0.5; }
  50% { opacity: 1; }
}

/* Particle Canvas Container */
.auth-particles {
  position: absolute;
  inset: 0;
  overflow: hidden;
}

/* Visual Panel Content */
.auth-visual-content {
  position: relative;
  z-index: 2;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  height: 100%;
  padding: var(--auth-space-3xl);
  text-align: center;
}

.auth-visual-logo {
  margin-bottom: var(--auth-space-2xl);
}

.auth-visual-logo img {
  height: 56px;
  width: auto;
  filter: drop-shadow(0 0 30px rgba(126, 103, 254, 0.3));
}

.auth-visual-tagline {
  max-width: 400px;
}

.auth-visual-tagline h2 {
  font-family: var(--auth-font-display);
  font-size: 2.25rem;
  font-weight: 600;
  color: var(--auth-text-primary);
  margin: 0 0 var(--auth-space-md);
  letter-spacing: -0.02em;
  line-height: 1.2;
}

.auth-visual-tagline p {
  font-size: 1.125rem;
  color: var(--auth-text-secondary);
  margin: 0;
  line-height: 1.7;
}

/* Floating Orbs */
.auth-orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(80px);
  opacity: 0.4;
  animation: orbFloat 20s ease-in-out infinite;
}

.auth-orb--primary {
  width: 400px;
  height: 400px;
  background: var(--auth-primary);
  top: 20%;
  left: 10%;
}

.auth-orb--secondary {
  width: 300px;
  height: 300px;
  background: #4f46e5;
  bottom: 20%;
  right: 10%;
  animation-delay: -10s;
}

@keyframes orbFloat {
  0%, 100% { transform: translate(0, 0) scale(1); }
  25% { transform: translate(30px, -20px) scale(1.05); }
  50% { transform: translate(-20px, 30px) scale(0.95); }
  75% { transform: translate(-30px, -10px) scale(1.02); }
}

/* Right Panel - Form */
.auth-form-panel {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 100%;
  min-height: 100vh;
  padding: var(--auth-space-lg);
  background: var(--auth-surface-base);
}

/* ═══════════════════════════════════════════════════════════════════
   4. CARD CONTAINER
   ═══════════════════════════════════════════════════════════════════ */
.auth-card {
  width: 100%;
  max-width: 440px;
  padding: var(--auth-space-2xl);
  background: var(--auth-surface-card);
  border: 1px solid var(--auth-border-default);
  border-radius: var(--auth-radius-xl);
  box-shadow: var(--auth-shadow-card), var(--auth-shadow-glow);
  position: relative;
  overflow: hidden;
}

/* Subtle top gradient accent */
.auth-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg,
    transparent 0%,
    var(--auth-primary) 50%,
    transparent 100%);
  opacity: 0.6;
}

/* ═══════════════════════════════════════════════════════════════════
   5. HEADER SECTION
   ═══════════════════════════════════════════════════════════════════ */
.auth-header {
  text-align: center;
  margin-bottom: var(--auth-space-xl);
}

.auth-logo {
  display: inline-block;
  margin-bottom: var(--auth-space-lg);
}

.auth-logo img {
  height: 44px;
  width: auto;
  transition: transform var(--auth-transition-normal);
}

.auth-logo:hover img {
  transform: scale(1.05);
}

.auth-heading {
  font-family: var(--auth-font-display);
  font-size: 1.875rem;
  font-weight: 600;
  color: var(--auth-text-primary);
  margin: 0 0 var(--auth-space-xs);
  letter-spacing: -0.02em;
}

.auth-subheading {
  font-size: 0.9375rem;
  color: var(--auth-text-secondary);
  margin: 0;
  font-weight: 400;
}

/* ═══════════════════════════════════════════════════════════════════
   6. FORM ELEMENTS
   ═══════════════════════════════════════════════════════════════════ */
.auth-form-group {
  margin-bottom: var(--auth-space-lg);
}

/* Labels */
.auth-label {
  display: block;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--auth-text-secondary);
  margin-bottom: var(--auth-space-sm);
  letter-spacing: 0.01em;
}

.auth-label-required::after {
  content: ' *';
  color: var(--auth-error);
}

/* Input Base */
.auth-input {
  display: block;
  width: 100%;
  padding: 0.875rem 1rem;
  font-size: 0.9375rem;
  font-family: var(--auth-font-body);
  line-height: 1.5;
  color: var(--auth-text-primary);
  background: var(--auth-surface-input);
  border: 1px solid var(--auth-border-default);
  border-radius: var(--auth-radius-md);
  box-shadow: var(--auth-shadow-input);
  transition:
    border-color var(--auth-transition-fast),
    box-shadow var(--auth-transition-fast),
    background-color var(--auth-transition-fast);
  min-height: 50px;
}

.auth-input::-moz-placeholder {
  color: var(--auth-text-muted);
}

.auth-input::placeholder {
  color: var(--auth-text-muted);
}

.auth-input:hover {
  border-color: var(--auth-border-emphasis);
  background: var(--auth-surface-elevated);
}

.auth-input:focus {
  outline: none;
  border-color: var(--auth-primary);
  background: var(--auth-surface-elevated);
  box-shadow:
    var(--auth-shadow-input),
    0 0 0 3px rgba(var(--auth-primary-rgb), 0.15);
}

.auth-input:disabled {
  background: var(--auth-surface-base);
  color: var(--auth-text-muted);
  cursor: not-allowed;
  opacity: 0.5;
}

.auth-input.filled {
  border-color: var(--auth-border-emphasis);
}

/* Error State */
.auth-input.error,
.auth-input.is-invalid {
  border-color: var(--auth-error);
  background: rgba(var(--auth-error-rgb), 0.05);
}

.auth-input.error:focus,
.auth-input.is-invalid:focus {
  box-shadow:
    var(--auth-shadow-input),
    0 0 0 3px rgba(var(--auth-error-rgb), 0.15);
}

/* Success State */
.auth-input.success {
  border-color: var(--auth-success);
}

.auth-input.success:focus {
  box-shadow:
    var(--auth-shadow-input),
    0 0 0 3px rgba(var(--auth-success-rgb), 0.15);
}

/* Password Wrapper */
.auth-password-wrapper {
  position: relative;
}

.auth-password-wrapper .auth-input {
  padding-right: 3rem;
}

.auth-password-toggle {
  position: absolute;
  right: 0.75rem;
  top: 50%;
  transform: translateY(-50%);
  background: none;
  border: none;
  color: var(--auth-text-tertiary);
  cursor: pointer;
  padding: 0.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: color var(--auth-transition-fast);
  border-radius: var(--auth-radius-sm);
}

.auth-password-toggle:hover {
  color: var(--auth-text-secondary);
}

.auth-password-toggle:focus {
  outline: none;
  color: var(--auth-primary);
}

.auth-password-toggle svg {
  width: 20px;
  height: 20px;
}

/* Error Messages */
.auth-error-message {
  display: flex;
  align-items: flex-start;
  gap: 0.375rem;
  margin-top: var(--auth-space-sm);
  font-size: 0.8125rem;
  color: var(--auth-error);
  font-weight: 500;
}

.auth-error-icon {
  flex-shrink: 0;
  margin-top: 1px;
}

/* Help Text */
.auth-help-text {
  margin-top: var(--auth-space-sm);
  font-size: 0.8125rem;
  color: var(--auth-text-tertiary);
}

/* ═══════════════════════════════════════════════════════════════════
   7. BUTTONS
   ═══════════════════════════════════════════════════════════════════ */
.auth-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.875rem 1.5rem;
  font-size: 0.9375rem;
  font-weight: 600;
  font-family: var(--auth-font-body);
  line-height: 1.5;
  text-align: center;
  text-decoration: none;
  border: none;
  border-radius: var(--auth-radius-md);
  cursor: pointer;
  transition:
    transform var(--auth-transition-fast),
    box-shadow var(--auth-transition-fast),
    background-color var(--auth-transition-fast);
  min-height: 50px;
  width: 100%;
  position: relative;
  overflow: hidden;
}

.auth-btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none !important;
}

/* Primary Button */
.auth-btn-primary {
  background: linear-gradient(135deg, var(--auth-primary) 0%, var(--auth-primary-dark) 100%);
  color: white;
  box-shadow: 0 4px 14px rgba(var(--auth-primary-rgb), 0.35);
}

.auth-btn-primary:hover:not(:disabled) {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(var(--auth-primary-rgb), 0.45);
}

.auth-btn-primary:active:not(:disabled) {
  transform: translateY(0);
  box-shadow: 0 2px 10px rgba(var(--auth-primary-rgb), 0.3);
}

/* Shimmer effect on hover */
.auth-btn-primary::after {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: linear-gradient(
    to right,
    transparent 0%,
    rgba(255, 255, 255, 0.1) 50%,
    transparent 100%
  );
  transform: rotate(45deg) translateX(-100%);
  transition: transform 0.6s ease;
}

.auth-btn-primary:hover::after {
  transform: rotate(45deg) translateX(100%);
}

/* Loading State */
.auth-btn.loading {
  color: transparent;
  pointer-events: none;
}

.auth-btn.loading::before {
  content: '';
  position: absolute;
  width: 22px;
  height: 22px;
  border: 2px solid rgba(255, 255, 255, 0.3);
  border-radius: 50%;
  border-top-color: white;
  animation: authSpinner 0.7s linear infinite;
}

@keyframes authSpinner {
  to { transform: rotate(360deg); }
}

/* ═══════════════════════════════════════════════════════════════════
   8. SOCIAL LOGIN
   ═══════════════════════════════════════════════════════════════════ */
.auth-social-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.75rem;
  width: 100%;
  padding: 0.875rem 1.5rem;
  font-size: 0.9375rem;
  font-weight: 500;
  font-family: var(--auth-font-body);
  background: var(--auth-surface-elevated);
  color: var(--auth-text-primary);
  border: 1px solid var(--auth-border-default);
  border-radius: var(--auth-radius-md);
  cursor: pointer;
  transition:
    background-color var(--auth-transition-fast),
    border-color var(--auth-transition-fast),
    transform var(--auth-transition-fast);
  text-decoration: none;
  min-height: 50px;
}

.auth-social-btn:hover {
  background: var(--auth-surface-hover);
  border-color: var(--auth-border-emphasis);
  transform: translateY(-1px);
}

.auth-social-btn svg {
  flex-shrink: 0;
  width: 20px;
  height: 20px;
}

.auth-social-help {
  text-align: center;
  margin-top: var(--auth-space-sm);
  font-size: 0.75rem;
  color: var(--auth-text-tertiary);
}

/* ═══════════════════════════════════════════════════════════════════
   9. DIVIDER
   ═══════════════════════════════════════════════════════════════════ */
.auth-divider {
  display: flex;
  align-items: center;
  text-align: center;
  margin: var(--auth-space-xl) 0;
}

.auth-divider::before,
.auth-divider::after {
  content: '';
  flex: 1;
  height: 1px;
  background: linear-gradient(
    90deg,
    transparent 0%,
    var(--auth-border-default) 50%,
    transparent 100%
  );
}

.auth-divider-text {
  padding: 0 var(--auth-space-md);
  font-size: 0.75rem;
  color: var(--auth-text-tertiary);
  font-weight: 500;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

/* ═══════════════════════════════════════════════════════════════════
   10. CHECKBOX & TERMS
   ═══════════════════════════════════════════════════════════════════ */
.auth-checkbox-wrapper {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
}

.auth-checkbox {
  flex-shrink: 0;
  width: 20px;
  height: 20px;
  margin-top: 2px;
  -webkit-appearance: none;
     -moz-appearance: none;
          appearance: none;
  background: var(--auth-surface-input);
  border: 1px solid var(--auth-border-default);
  border-radius: 5px;
  cursor: pointer;
  transition: all var(--auth-transition-fast);
  position: relative;
}

.auth-checkbox:checked {
  background: var(--auth-primary);
  border-color: var(--auth-primary);
}

.auth-checkbox:checked::after {
  content: '';
  position: absolute;
  top: 3px;
  left: 6px;
  width: 5px;
  height: 10px;
  border: solid white;
  border-width: 0 2px 2px 0;
  transform: rotate(45deg);
}

.auth-checkbox:focus {
  outline: none;
  box-shadow: 0 0 0 3px rgba(var(--auth-primary-rgb), 0.2);
}

.auth-checkbox:hover {
  border-color: var(--auth-border-emphasis);
}

.auth-checkbox-label {
  font-size: 0.8125rem;
  color: var(--auth-text-secondary);
  line-height: 1.6;
  cursor: pointer;
}

.auth-checkbox-label a {
  color: var(--auth-primary-light);
  text-decoration: none;
  font-weight: 500;
  transition: color var(--auth-transition-fast);
}

.auth-checkbox-label a:hover {
  color: var(--auth-primary);
  text-decoration: underline;
}

/* ═══════════════════════════════════════════════════════════════════
   11. PASSWORD STRENGTH INDICATOR
   ═══════════════════════════════════════════════════════════════════ */
.auth-password-strength {
  margin-top: var(--auth-space-md);
}

.auth-strength-meter {
  display: flex;
  gap: 0.375rem;
  margin-bottom: var(--auth-space-sm);
}

.auth-strength-bar {
  flex: 1;
  height: 4px;
  background: var(--auth-surface-elevated);
  border-radius: 2px;
  transition: background-color var(--auth-transition-normal);
  overflow: hidden;
}

.auth-strength-bar.active {
  position: relative;
}

.auth-strength-bar.active::after {
  content: '';
  position: absolute;
  inset: 0;
  background: inherit;
  animation: strengthPulse 2s ease-in-out infinite;
}

@keyframes strengthPulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.7; }
}

.auth-strength-bar.active.weak { background: var(--auth-error); }
.auth-strength-bar.active.fair { background: var(--auth-warning); }
.auth-strength-bar.active.good { background: var(--auth-info); }
.auth-strength-bar.active.strong { background: var(--auth-success); }

.auth-strength-text {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--auth-text-tertiary);
  display: flex;
  align-items: center;
  gap: 0.375rem;
}

.auth-strength-text.weak { color: var(--auth-error); }
.auth-strength-text.fair { color: var(--auth-warning); }
.auth-strength-text.good { color: var(--auth-info); }
.auth-strength-text.strong { color: var(--auth-success); }

/* ═══════════════════════════════════════════════════════════════════
   12. FOOTER & LINKS
   ═══════════════════════════════════════════════════════════════════ */
.auth-footer {
  margin-top: var(--auth-space-xl);
  padding-top: var(--auth-space-lg);
  border-top: 1px solid var(--auth-border-default);
}

.auth-footer-text {
  text-align: center;
  font-size: 0.875rem;
  color: var(--auth-text-secondary);
  margin: 0;
}

.auth-footer-link {
  color: var(--auth-primary-light);
  text-decoration: none;
  font-weight: 600;
  transition: color var(--auth-transition-fast);
}

.auth-footer-link:hover {
  color: var(--auth-primary);
}

.auth-security-badge {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  margin-top: var(--auth-space-lg);
  padding: 0.75rem var(--auth-space-md);
  background: rgba(var(--auth-success-rgb), 0.08);
  border: 1px solid rgba(var(--auth-success-rgb), 0.15);
  border-radius: var(--auth-radius-md);
  font-size: 0.75rem;
  color: var(--auth-success);
  font-weight: 500;
}

.auth-security-icon {
  flex-shrink: 0;
}

/* ═══════════════════════════════════════════════════════════════════
   13. ALERTS & NOTIFICATIONS
   ═══════════════════════════════════════════════════════════════════ */
.auth-alert {
  display: flex;
  align-items: center;
  gap: 0.625rem;
  padding: 0.875rem var(--auth-space-md);
  border-radius: var(--auth-radius-md);
  margin-bottom: var(--auth-space-lg);
  font-size: 0.875rem;
  font-weight: 500;
}

.auth-alert-success {
  background: rgba(var(--auth-success-rgb), 0.1);
  border: 1px solid rgba(var(--auth-success-rgb), 0.2);
  color: var(--auth-success);
}

.auth-alert-error {
  background: rgba(var(--auth-error-rgb), 0.1);
  border: 1px solid rgba(var(--auth-error-rgb), 0.2);
  color: var(--auth-error);
}

.auth-alert-info {
  background: rgba(59, 130, 246, 0.1);
  border: 1px solid rgba(59, 130, 246, 0.2);
  color: var(--auth-info);
}

.auth-success-icon {
  flex-shrink: 0;
}

/* ═══════════════════════════════════════════════════════════════════
   14. FEATURE LIST (for visual panel)
   ═══════════════════════════════════════════════════════════════════ */
.auth-features {
  margin-top: var(--auth-space-2xl);
  display: flex;
  flex-direction: column;
  gap: var(--auth-space-md);
}

.auth-feature {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 0.9375rem;
  color: var(--auth-text-secondary);
}

.auth-feature-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  background: rgba(var(--auth-primary-rgb), 0.15);
  border-radius: 8px;
  color: var(--auth-primary-light);
}

.auth-feature-icon svg {
  width: 18px;
  height: 18px;
}

/* ═══════════════════════════════════════════════════════════════════
   15. RESPONSIVE DESIGN
   ═══════════════════════════════════════════════════════════════════ */

/* Tablet and up - Show split screen */
@media (min-width: 1024px) {
  .auth-visual-panel {
    display: block;
    flex: 1;
    max-width: 55%;
  }

  .auth-form-panel {
    flex: 0 0 45%;
    max-width: 600px;
  }

  .auth-card {
    max-width: 420px;
  }

  /* Hide mobile logo when visual panel is shown */
  .auth-card .auth-logo {
    display: none;
  }
}

/* Large screens */
@media (min-width: 1440px) {
  .auth-visual-tagline h2 {
    font-size: 2.75rem;
  }

  .auth-visual-tagline p {
    font-size: 1.25rem;
  }

  .auth-card {
    padding: var(--auth-space-3xl);
    max-width: 460px;
  }
}

/* Mobile optimizations */
@media (max-width: 640px) {
  .auth-form-panel {
    padding: var(--auth-space-md);
  }

  .auth-card {
    padding: var(--auth-space-xl);
    border-radius: var(--auth-radius-lg);
  }

  .auth-heading {
    font-size: 1.5rem;
  }

  .auth-btn,
  .auth-social-btn,
  .auth-input {
    min-height: 48px;
  }
}

/* ═══════════════════════════════════════════════════════════════════
   16. ACCESSIBILITY
   ═══════════════════════════════════════════════════════════════════ */

/* Focus visible for keyboard navigation */
.auth-input:focus-visible,
.auth-btn:focus-visible,
.auth-checkbox:focus-visible,
.auth-social-btn:focus-visible,
.auth-password-toggle:focus-visible,
.auth-footer-link:focus-visible {
  outline: 2px solid var(--auth-primary);
  outline-offset: 2px;
}

/* Screen reader only */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}

/* High contrast mode */
@media (prefers-contrast: high) {
  .auth-input,
  .auth-btn,
  .auth-social-btn,
  .auth-checkbox {
    border-width: 2px;
  }
}

/* Reduced motion */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }

  .auth-particles {
    display: none;
  }
}

/* ═══════════════════════════════════════════════════════════════════
   17. UTILITY CLASSES
   ═══════════════════════════════════════════════════════════════════ */
.text-center { text-align: center; }
.text-primary { color: var(--auth-primary-light); }

.mt-xs { margin-top: var(--auth-space-xs); }
.mt-sm { margin-top: var(--auth-space-sm); }
.mt-md { margin-top: var(--auth-space-md); }
.mt-lg { margin-top: var(--auth-space-lg); }

.mb-xs { margin-bottom: var(--auth-space-xs); }
.mb-sm { margin-bottom: var(--auth-space-sm); }
.mb-md { margin-bottom: var(--auth-space-md); }
.mb-lg { margin-bottom: var(--auth-space-lg); }

/* ═══════════════════════════════════════════════════════════════════
   18. PARTICLE ANIMATION STYLES
   ═══════════════════════════════════════════════════════════════════ */
.particle {
  position: absolute;
  width: 4px;
  height: 4px;
  background: var(--auth-primary);
  border-radius: 50%;
  opacity: 0.6;
  animation: particleFloat 15s infinite ease-in-out;
}

.particle::before {
  content: '';
  position: absolute;
  width: 100%;
  height: 100%;
  background: inherit;
  border-radius: inherit;
  filter: blur(4px);
  transform: scale(2);
  opacity: 0.5;
}

@keyframes particleFloat {
  0%, 100% {
    transform: translate(0, 0);
    opacity: 0.6;
  }
  25% {
    transform: translate(20px, -30px);
    opacity: 0.8;
  }
  50% {
    transform: translate(-15px, 20px);
    opacity: 0.4;
  }
  75% {
    transform: translate(25px, 15px);
    opacity: 0.7;
  }
}

/* Connection lines between particles */
.connection-line {
  position: absolute;
  height: 1px;
  background: linear-gradient(90deg,
    transparent 0%,
    rgba(var(--auth-primary-rgb), 0.3) 50%,
    transparent 100%);
  transform-origin: left center;
  animation: connectionPulse 4s infinite ease-in-out;
}

@keyframes connectionPulse {
  0%, 100% { opacity: 0.2; }
  50% { opacity: 0.5; }
}