/* ============================================================
   NEBULA PAGES — nebula-pages.css
   Page-specific styles for Home, Auth, Free Exam/Class pages.
   ============================================================ */

/* ═══════════════════════════════════════════════════════════
   HOME PAGE
   ═══════════════════════════════════════════════════════════ */

/* ─── Hero Section ─── */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  padding: var(--space-4xl) var(--container-padding) var(--space-3xl);
  text-align: center;
}

#hero-canvas {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 1;
  pointer-events: none;
}

.hero__content {
  position: relative;
  z-index: 2;
  max-width: 1200px;
  margin: 0 auto;
}

.hero__badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: 8px 20px;
  background: rgba(255, 255, 255, 0.8);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border: 1px solid rgba(0, 0, 0, 0.05);
  border-radius: var(--radius-full);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: var(--weight-medium);
  color: var(--color-text-secondary);
  margin-bottom: var(--space-xl);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
}

.hero__badge-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--color-success);
  animation: pulse-dot 2s ease-in-out infinite;
}

.hero__title {
  font-family: var(--font-hero);
  font-weight: 400;
  font-style: normal;
  font-size: clamp(2.5rem, 5.5vw, 5rem);
  line-height: 1.05;
  color: var(--color-text-primary);
  margin-bottom: var(--space-lg);
  letter-spacing: -0.02em;
}

.hero__title-accent {
  position: relative;
  display: inline-block;
}



.hero__subtitle {
  font-family: var(--font-body);
  font-weight: var(--weight-medium);
  font-size: clamp(var(--text-base), 2vw, var(--text-xl));
  color: var(--color-text-secondary);
  line-height: var(--leading-relaxed);
  max-width: 640px;
  margin: 0 auto var(--space-2xl) auto;
}

.hero__cta {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-md);
  flex-wrap: wrap;
}

.hero__scroll-indicator {
  position: absolute;
  bottom: var(--space-xl);
  left: 50%;
  transform: translateX(-50%);
  z-index: 2;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-sm);
  color: var(--color-text-muted);
}

.hero__scroll-line {
  width: 1px;
  height: 40px;
  background: linear-gradient(to bottom, var(--color-text-muted), transparent);
  animation: scroll-indicator 2s ease-in-out infinite;
}

.hero__scroll-text {
  font-size: var(--text-xs);
  font-family: var(--font-mono);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  writing-mode: vertical-rl;
  text-orientation: mixed;
}

/* ─── Premium Featured Live Class ─── */
.featured-live {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: var(--space-2xl);
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-2xl);
  padding: var(--space-xl);
  backdrop-filter: blur(20px);
  position: relative;
  overflow: hidden;
}

.featured-live__thumbnail-wrapper {
  position: relative;
  border-radius: var(--radius-xl);
  padding: 4px; /* Space for the premium border */
  background: linear-gradient(135deg, #FF3D00, #FF8F00, #FF3D00);
  background-size: 200% 200%;
  animation: premium-border-flow 4s linear infinite;
  box-shadow: 0 0 30px rgba(255, 61, 0, 0.3);
}

.featured-live__thumbnail {
  width: 100%;
  aspect-ratio: 16/9;
  object-fit: cover;
  border-radius: calc(var(--radius-xl) - 4px);
  display: block;
}

.featured-live__content {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: var(--space-md);
}

.featured-live__badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: rgba(255, 61, 0, 0.1);
  color: #FF3D00;
  padding: 6px 16px;
  border-radius: var(--radius-full);
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: var(--weight-bold);
  letter-spacing: 0.1em;
  width: fit-content;
}

.featured-live__dot {
  width: 8px;
  height: 8px;
  background: #FF3D00;
  border-radius: 50%;
  animation: pulse-dot-red 1.5s infinite;
}

.featured-live__title {
  font-family: var(--font-display);
  font-size: var(--text-3xl);
  line-height: 1.1;
  color: var(--color-text-primary);
}

.featured-live__desc {
  color: var(--color-text-secondary);
  font-size: var(--text-base);
  max-width: 450px;
}

.featured-live__link {
  margin-top: var(--space-sm);
  font-family: var(--font-display);
  font-weight: var(--weight-bold);
  font-size: var(--text-lg);
  color: #FF3D00;
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 8px;
  transition: all var(--transition-fast);
}

.featured-live__link:hover {
  transform: translateX(8px);
  opacity: 0.8;
}

@keyframes premium-border-flow {
  0% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}

@keyframes pulse-dot-red {
  0% { transform: scale(0.9); opacity: 0.7; box-shadow: 0 0 0 0 rgba(255, 61, 0, 0.4); }
  70% { transform: scale(1.1); opacity: 1; box-shadow: 0 0 0 10px rgba(255, 61, 0, 0); }
  100% { transform: scale(0.9); opacity: 0.7; box-shadow: 0 0 0 0 rgba(255, 61, 0, 0); }
}

@media (max-width: 992px) {
  .featured-live {
    grid-template-columns: 1fr;
  }
}

/* ─── Courses Section ─── */

.section-courses {
  padding: var(--space-4xl) 0;
  position: relative;
}

.courses-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: var(--space-lg);
}

.courses-filter {
  margin-bottom: var(--space-xl);
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-md);
}

/* ─── Nebula AI Section ─── */
.section-ai {
  padding: var(--space-4xl) 0;
  position: relative;
  overflow: hidden;
}

.ai-section__layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-3xl);
  align-items: center;
}

.ai-section__content {
  max-width: 500px;
}

.ai-section__title {
  font-family: var(--font-hero);
  font-weight: 400;
  font-style: normal;
  font-size: clamp(var(--text-3xl), 3.5vw, var(--text-5xl));
  color: var(--color-text-primary);
  line-height: 1.05;
  letter-spacing: -0.035em;
  margin-bottom: var(--space-lg);
}

.ai-section__desc {
  font-size: var(--text-lg);
  font-weight: var(--weight-body);
  color: var(--color-text-secondary);
  line-height: var(--leading-relaxed);
  margin-bottom: var(--space-xl);
}

.ai-section__features {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
  margin-bottom: var(--space-xl);
}

.ai-section__feature {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  font-weight: var(--weight-semibold);
}

.ai-section__feature-check {
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: var(--color-accent);
  color: #FFFFFF;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 12px;
  flex-shrink: 0;
}

.ai-section__visual {
  display: flex;
  justify-content: flex-end;
}

/* ─── AI Extra Sections (Coming Soon) ─── */
.ai-section__extra {
  margin-top: var(--space-3xl);
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-xl);
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  padding-top: var(--space-2xl);
}

.ai-extra-card {
  background: rgba(255, 255, 255, 0.03);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: var(--radius-xl);
  padding: var(--space-xl);
  position: relative;
  overflow: hidden;
  transition: all var(--transition-normal);
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.ai-extra-card:hover {
  background: rgba(255, 255, 255, 0.05);
  border-color: rgba(255, 255, 255, 0.15);
  transform: translateY(-4px);
}

.ai-extra-card__badge {
  display: inline-flex;
  align-items: center;
  padding: 4px 12px;
  background: var(--color-accent-subtle);
  color: var(--color-accent);
  border-radius: var(--radius-full);
  font-size: 10px;
  font-weight: var(--weight-bold);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  width: fit-content;
  margin-bottom: var(--space-xs);
}

.ai-extra-card__title {
  font-family: var(--font-display);
  font-size: var(--text-xl);
  color: var(--color-text-primary);
  margin-bottom: 4px;
}

.ai-extra-card__desc {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  line-height: var(--leading-relaxed);
}

.ai-extra-card__icon {
  position: absolute;
  top: var(--space-xl);
  right: var(--space-xl);
  opacity: 0.1;
  transform: scale(2.5);
  color: var(--color-text-primary);
}


/* ─── Free Exam Section ─── */
.section-free-exam {
  padding: var(--space-4xl) 0;
  background: transparent;
  position: relative;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
}

.free-exam-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: var(--space-lg);
}

/* ─── Free Live Class Section ─── */
.section-free-class {
  padding: var(--space-4xl) 0;
  position: relative;
}

.free-class-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: var(--space-lg);
}

.stats-bar {
  padding: var(--space-3xl) 0;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
  background: transparent;
}

.stats-bar__grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-xl);
  text-align: center;
}

.stats-bar__item-number {
  font-family: var(--font-display);
  font-weight: var(--weight-extrabold);
  font-size: var(--text-4xl);
  color: var(--color-text-primary);
  line-height: 1;
  margin-bottom: var(--space-xs);
}

.stats-bar__item-label {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  font-weight: var(--weight-medium);
}

/* ─── CTA Banner Section ─── */
.section-cta {
  padding: 0;
}

.cta-banner {
  background: var(--color-bg-soft);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-2xl);
  padding: var(--space-4xl) var(--space-2xl);
  text-align: center;
  position: relative;
  overflow: hidden;
}

.cta-banner__title {
  font-family: var(--font-hero);
  font-weight: 400;
  font-style: normal;
  font-size: clamp(var(--text-3xl), 5vw, var(--text-5xl));
  color: var(--color-text-primary);
  margin-bottom: var(--space-md);
  letter-spacing: -0.02em;
}

.cta-banner__desc {
  font-size: var(--text-lg);
  font-weight: var(--weight-medium);
  color: var(--color-text-secondary);
  max-width: 500px;
  margin: 0 auto var(--space-2xl);
}

.cta-banner__pattern {
  position: absolute;
  inset: 0;
  background-image: radial-gradient(circle, var(--color-border) 1px, transparent 1px);
  background-size: 32px 32px;
  pointer-events: none;
}

/* ═══════════════════════════════════════════════════════════
   AUTH PAGE
   ═══════════════════════════════════════════════════════════ */
.auth-page {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-xl);
  background: radial-gradient(circle at center, #0a0a0a 0%, #000000 100%);
  position: relative;
  overflow: hidden;
}

.auth-card {
  width: 100%;
  max-width: 460px;
  background: rgba(10, 10, 10, 0.4);
  backdrop-filter: blur(40px) saturate(180%);
  -webkit-backdrop-filter: blur(40px) saturate(180%);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 24px;
  box-shadow: 
    0 24px 80px rgba(0, 0, 0, 0.8),
    inset 0 0 0 1px rgba(255, 255, 255, 0.05);
  padding: var(--space-2xl);
  position: relative;
  z-index: 2;
  transition: transform 0.4s cubic-bezier(0.23, 1, 0.32, 1);
}

.auth-card::before {
  content: '';
  position: absolute;
  top: -1px;
  left: -1px;
  right: -1px;
  bottom: -1px;
  border-radius: 24px;
  padding: 1px;
  background: linear-gradient(135deg, rgba(255,255,255,0.2), transparent, rgba(255,255,255,0.1));
  -webkit-mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
  mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
  -webkit-mask-composite: xor;
  mask-composite: exclude;
  pointer-events: none;
}

.auth-card__header {
  text-align: center;
  margin-bottom: var(--space-xl);
}

.auth-card__logo {
  font-family: var(--font-display);
  font-weight: var(--weight-extrabold);
  font-size: var(--text-3xl);
  color: var(--color-text-primary);
  margin-bottom: var(--space-sm);
}

.auth-card__title {
  font-family: var(--font-display);
  font-weight: var(--weight-semibold);
  font-size: var(--text-xl);
  color: var(--color-text-primary);
  margin-bottom: var(--space-xs);
}

.auth-card__subtitle {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}

.auth-card__form {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.auth-card__toggle {
  text-align: center;
  margin-top: var(--space-lg);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}

.auth-card__toggle a {
  color: var(--color-text-primary);
  font-weight: var(--weight-semibold);
  text-decoration: underline;
  text-underline-offset: 2px;
}

.auth-tabs {
  display: flex;
  background: rgba(255, 255, 255, 0.05);
  border-radius: 100px;
  padding: 6px;
  margin-bottom: var(--space-xl);
  border: 1px solid rgba(255, 255, 255, 0.08);
}

.auth-tabs__item {
  flex: 1;
  text-align: center;
  padding: 10px 20px;
  border-radius: 100px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--text-sm);
  color: rgba(255, 255, 255, 0.3);
  cursor: pointer;
  border: none;
  background: transparent;
  transition: all 0.4s cubic-bezier(0.23, 1, 0.32, 1);
  letter-spacing: 0.02em;
}

.auth-tabs__item.active {
  background: #FFFFFF;
  color: #000000;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
}

/* ─── OTP Input ─── */
.otp-inputs {
  display: flex;
  gap: var(--space-sm);
  justify-content: center;
  margin: var(--space-xl) 0;
}

.otp-input {
  width: 52px;
  height: 60px;
  border: 2px solid rgba(255, 255, 255, 0.12);
  border-radius: var(--radius-md);
  text-align: center;
  font-family: var(--font-mono);
  font-size: var(--text-2xl);
  font-weight: var(--weight-bold);
  color: var(--color-text-primary);
  outline: none;
  transition: all var(--transition-fast);
  background: rgba(255, 255, 255, 0.04);
}

.otp-input:focus {
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px rgba(200, 255, 0, 0.1);
}

.otp-input--filled {
  border-color: var(--color-accent);
  background: var(--color-accent-subtle);
}

.otp-timer {
  text-align: center;
  font-family: var(--font-mono);
  font-size: var(--text-2xl);
  font-weight: var(--weight-bold);
  color: var(--color-text-primary);
  margin-bottom: var(--space-md);
}

.otp-resend {
  text-align: center;
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}

.otp-resend button {
  background: transparent;
  border: none;
  color: var(--color-text-primary);
  font-weight: var(--weight-semibold);
  cursor: pointer;
  text-decoration: underline;
  text-underline-offset: 2px;
}

.otp-resend button:disabled {
  color: var(--color-text-muted);
  cursor: not-allowed;
  text-decoration: none;
}

/* ─── Password Strength Indicator ─── */
.password-strength {
  display: flex;
  gap: 4px;
  margin-top: 4px;
}

.password-strength__bar {
  flex: 1;
  height: 3px;
  border-radius: 3px;
  background: var(--color-bg-muted);
  transition: background var(--transition-fast);
}

.password-strength__bar.active {
  background: var(--color-error);
}

.password-strength__bar.active:nth-child(-n+2) {
  background: var(--color-warning);
}

.password-strength__bar.active:nth-child(-n+3) {
  background: var(--color-success);
}

.password-strength__bar.active:nth-child(-n+4) {
  background: var(--color-success);
}

/* ═══════════════════════════════════════════════════════════
   RESPONSIVE — HOME PAGE
   ═══════════════════════════════════════════════════════════ */
/* ═══════════════════════════════════════════════════════════
   RESPONSIVE — Tablet Landscape (≤1200px)
   ═══════════════════════════════════════════════════════════ */
@media (max-width: 1200px) {
  .ai-section__layout {
    gap: var(--space-2xl);
  }

  .section-courses,
  .section-ai,
  .section-exams,
  .section-classes {
    padding: var(--space-3xl) 0;
  }

  .cta-banner {
    padding: var(--space-2xl) var(--space-xl);
  }
}

/* ═══════════════════════════════════════════════════════════
   RESPONSIVE — Tablet Portrait / Mobile Landscape (≤768px)
   ═══════════════════════════════════════════════════════════ */
@media (max-width: 768px) {
  .hero {
    min-height: 85vh;
    padding: var(--space-2xl) var(--container-padding) var(--space-xl);
  }

  .hero__title {
    font-size: clamp(1.75rem, 7vw, 2.5rem);
  }

  .hero__title-line {
    white-space: normal;
  }

  .hero__subtitle {
    font-size: var(--text-base);
    max-width: 90%;
  }

  .hero__cta {
    flex-direction: column;
    width: 100%;
  }

  .hero__cta .btn {
    width: 100%;
    justify-content: center;
  }

  .hero__scroll-indicator {
    display: none;
  }

  .hero__badge {
    font-size: 11px;
    padding: 8px 16px;
  }

  /* AI Section */
  .ai-section__layout {
    grid-template-columns: 1fr;
    gap: var(--space-xl);
  }

  .ai-section__visual {
    justify-content: center;
    order: -1;
  }

  .ai-section__extra {
    grid-template-columns: 1fr;
    gap: var(--space-md);
  }


  .ai-section__content {
    max-width: 100%;
    text-align: center;
  }

  .ai-section__title {
    font-size: clamp(var(--text-2xl), 5vw, var(--text-3xl));
  }

  .ai-section__features {
    align-items: center;
  }

  .ai-chat-window {
    max-width: 340px;
    margin: 0 auto;
  }

  /* Grids */
  .courses-grid,
  .free-exam-grid,
  .free-class-grid {
    grid-template-columns: 1fr;
  }

  .stats-bar__grid {
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-lg);
  }

  .courses-filter {
    flex-direction: column;
    align-items: flex-start;
  }

  /* CTA Banner */
  .cta-banner {
    padding: var(--space-2xl) var(--space-lg);
    border-radius: var(--radius-lg);
    margin: 0 var(--space-md);
  }

  .cta-banner__title {
    font-size: clamp(var(--text-xl), 5vw, var(--text-3xl));
  }

  .cta-banner__desc {
    font-size: var(--text-base);
  }

  /* Section headers */
  .section-header {
    margin-bottom: var(--space-xl);
  }

  .section-header__title {
    font-size: clamp(var(--text-2xl), 5vw, var(--text-3xl));
  }

  /* Sections padding */
  .section-courses,
  .section-ai,
  .section-exams,
  .section-classes {
    padding: var(--space-2xl) 0;
  }

  /* Data tables horizontal scroll */
  .data-table-container,
  .data-table-wrapper {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
  }

  .data-table {
    min-width: 600px;
  }
}

/* ═══════════════════════════════════════════════════════════
   RESPONSIVE — Mobile Portrait (≤480px)
   ═══════════════════════════════════════════════════════════ */
@media (max-width: 480px) {
  .hero {
    min-height: 80vh;
    padding: var(--space-xl) var(--space-md) var(--space-lg);
  }

  .hero__title {
    font-size: clamp(1.5rem, 8vw, 2.2rem);
    letter-spacing: -0.01em;
  }

  .hero__subtitle {
    font-size: var(--text-sm);
    max-width: 100%;
  }

  .hero__cta .btn--xl {
    padding: 14px 24px;
    font-size: var(--text-sm);
  }

  /* Auth */
  .auth-card {
    padding: var(--space-lg);
    border: none;
    box-shadow: none;
    border-radius: 0;
  }

  .auth-card__title {
    font-size: var(--text-2xl);
  }

  .otp-input {
    width: 42px;
    height: 50px;
    font-size: var(--text-lg);
  }

  /* Stats */
  .stats-bar__grid {
    grid-template-columns: 1fr 1fr;
    gap: var(--space-md);
  }

  .stats-bar__number {
    font-size: var(--text-3xl);
  }

  /* CTA */
  .cta-banner {
    padding: var(--space-xl) var(--space-md);
    margin: 0;
    border-radius: var(--radius-md);
  }

  /* AI chat */
  .ai-chat-window {
    max-width: 280px;
  }

  .ai-section__title {
    font-size: var(--text-xl);
  }

  /* Section headers */
  .section-header__title {
    font-size: var(--text-2xl);
  }

  .section-header__desc {
    font-size: var(--text-sm);
  }

  /* Sections */
  .section-courses,
  .section-ai,
  .section-exams,
  .section-classes {
    padding: var(--space-xl) 0;
  }
}

/* ═══════════════════════════════════════════════════════════
   DATA TABLES (Admin Dashboard)
   ═══════════════════════════════════════════════════════════ */
.data-table {
  width: 100%;
  border-collapse: collapse;
  font-family: var(--font-body);
  font-size: var(--text-sm);
}

.data-table thead {
  border-bottom: 2px solid var(--color-border);
}

.data-table th {
  text-align: left;
  padding: var(--space-md) var(--space-lg);
  font-weight: var(--weight-semibold);
  color: var(--color-text-muted);
  font-size: var(--text-xs);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  white-space: nowrap;
}

.data-table td {
  padding: var(--space-md) var(--space-lg);
  border-bottom: 1px solid var(--color-border-subtle, rgba(0,0,0,0.04));
  color: var(--color-text-secondary);
  vertical-align: middle;
}

.data-table tbody tr {
  transition: background var(--transition-fast);
}

.data-table tbody tr:hover {
  background: var(--color-accent-subtle);
}

.data-table tbody tr:last-child td {
  border-bottom: none;
}

/* ═══════════════════════════════════════════════════════════
   MODALS
   ═══════════════════════════════════════════════════════════ */
.modal-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.5);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  z-index: var(--z-modal, 1000);
  align-items: center;
  justify-content: center;
}

.modal-overlay.active {
  display: flex;
}

.modal {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-xl);
  max-width: 480px;
  width: 90%;
  max-height: 85vh;
  overflow-y: auto;
}

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-lg) var(--space-xl);
  border-bottom: 1px solid var(--color-border);
}

.modal-header h3 {
  font-family: var(--font-display);
  font-weight: var(--weight-semibold);
  font-size: var(--text-lg);
  color: var(--color-text-primary);
}

.modal-body {
  padding: var(--space-xl);
}

.modal-footer {
  display: flex;
  justify-content: flex-end;
  gap: var(--space-sm);
  padding: var(--space-md) var(--space-xl) var(--space-lg);
  border-top: 1px solid var(--color-border);
}

/* ═══════════════════════════════════════════════════════════
   STAT CARDS
   ═══════════════════════════════════════════════════════════ */
.stat-card {
  padding: var(--space-xl);
  text-align: center;
}

.stat-card__number {
  font-family: var(--font-display);
  font-weight: var(--weight-extrabold);
  font-size: var(--text-4xl);
  color: var(--color-text-primary);
  line-height: 1;
  margin-bottom: var(--space-xs);
}

.stat-card__label {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  font-weight: var(--weight-medium);
}

/* ═══════════════════════════════════════════════════════════
   EMPTY STATES
   ═══════════════════════════════════════════════════════════ */
.empty-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: var(--space-3xl);
}

.empty-state__icon {
  font-size: 48px;
  margin-bottom: var(--space-md);
  line-height: 1;
}

.empty-state__title {
  font-family: var(--font-display);
  font-weight: var(--weight-semibold);
  font-size: var(--text-lg);
  color: var(--color-text-primary);
  margin-bottom: var(--space-sm);
}

.empty-state__desc {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  max-width: 400px;
}

/* ═══════════════════════════════════════════════════════════
   EXAM ENGINE INTERFACE
   ═══════════════════════════════════════════════════════════ */
.exam-page {
  min-height: 100vh;
  background: var(--color-bg);
}

.exam-interface {
  position: fixed;
  inset: 0;
  background: var(--color-bg);
  z-index: 100;
  display: flex;
  flex-direction: column;
}

.exam-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-md) var(--space-xl);
  border-bottom: 1px solid var(--color-border);
  background: var(--color-bg);
  flex-shrink: 0;
}

.exam-header__title {
  font-family: var(--font-display);
  font-weight: var(--weight-semibold);
  font-size: var(--text-lg);
  color: var(--color-text-primary);
}

.exam-header__timer {
  font-family: var(--font-mono);
  font-weight: var(--weight-bold);
  font-size: var(--text-2xl);
  color: var(--color-text-primary);
  padding: var(--space-xs) var(--space-md);
  background: var(--color-bg-muted);
  border-radius: var(--radius-md);
  letter-spacing: 0.05em;
}

.exam-body {
  flex: 1;
  display: flex;
  overflow: hidden;
}

.exam-nav {
  width: 200px;
  padding: var(--space-lg);
  border-right: 1px solid var(--color-border);
  overflow-y: auto;
  flex-shrink: 0;
}

.exam-nav__grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 4px;
}

.exam-nav__btn {
  width: 36px;
  height: 36px;
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-bg);
  color: var(--color-text-secondary);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: var(--weight-semibold);
  cursor: pointer;
  transition: all var(--transition-fast);
  display: flex;
  align-items: center;
  justify-content: center;
}

.exam-nav__btn:hover {
  border-color: var(--color-text-primary);
  background: var(--color-accent-subtle);
}

.exam-nav__btn.current {
  border-color: var(--color-accent);
  background: var(--color-accent);
  color: var(--color-text-inverse);
}

.exam-nav__btn.answered {
  background: var(--color-success);
  border-color: var(--color-success);
  color: #FFFFFF;
}

.exam-nav__btn.answered.current {
  background: var(--color-accent);
  border-color: var(--color-accent);
}

.exam-question-area {
  flex: 1;
  padding: var(--space-2xl);
  overflow-y: auto;
  max-width: 800px;
}

.exam-question__number {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: var(--weight-semibold);
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: var(--space-md);
}

.exam-question__text {
  font-family: var(--font-display);
  font-weight: var(--weight-semibold);
  font-size: var(--text-xl);
  color: var(--color-text-primary);
  line-height: var(--leading-relaxed);
  margin-bottom: var(--space-xl);
}

.exam-question__options {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.exam-option {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding: var(--space-md) var(--space-lg);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-fast);
  background: var(--color-bg);
}

.exam-option:hover {
  border-color: var(--color-text-muted);
  background: var(--color-bg-soft);
}

.exam-option.selected {
  border-color: var(--color-accent);
  background: var(--color-accent-subtle);
}

.exam-option input[type="radio"] {
  display: none;
}

.exam-option__label {
  width: 30px;
  height: 30px;
  border-radius: 50%;
  border: 2px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-display);
  font-weight: var(--weight-bold);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  flex-shrink: 0;
  transition: all var(--transition-fast);
}

.exam-option.selected .exam-option__label {
  background: var(--color-accent);
  border-color: var(--color-accent);
  color: var(--color-text-inverse);
}

.exam-option__text {
  font-size: var(--text-base);
  color: var(--color-text-secondary);
  font-weight: var(--weight-medium);
}

.exam-question-nav {
  display: flex;
  justify-content: space-between;
  margin-top: var(--space-2xl);
  padding-top: var(--space-lg);
  border-top: 1px solid var(--color-border);
}

/* ═══════════════════════════════════════════════════════════
   LIVE CLASS VIEWER
   ═══════════════════════════════════════════════════════════ */
.free-class-page {
  min-height: 100vh;
  background: var(--color-bg);
}

.class-viewer {
  display: grid;
  grid-template-columns: 1fr 340px;
  height: 100vh;
  background: #0a0a0a;
}

.class-viewer__video {
  display: flex;
  flex-direction: column;
  padding: var(--space-md);
  position: relative;
}

.class-viewer__video-container {
  flex: 1;
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  border-radius: var(--radius-md);
}

.class-viewer__drm-notice {
  position: absolute;
  top: var(--space-md);
  right: var(--space-md);
  padding: 6px 12px;
  background: rgba(255, 0, 0, 0.15);
  border: 1px solid rgba(255, 0, 0, 0.3);
  border-radius: var(--radius-sm);
  font-size: 10px;
  color: rgba(255, 100, 100, 0.8);
  font-family: var(--font-mono);
  pointer-events: none;
}

.class-viewer__controls {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-md) 0 var(--space-sm);
}

.class-viewer__controls-left {
  display: flex;
  align-items: center;
  gap: var(--space-md);
}

.class-viewer__controls-right {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.class-viewer__chat {
  display: flex;
  flex-direction: column;
  border-left: 1px solid rgba(255, 255, 255, 0.08);
  background: rgba(255, 255, 255, 0.02);
}

.class-viewer__chat-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-md) var(--space-lg);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
  color: #FFFFFF;
}

.class-viewer__chat-messages {
  flex: 1;
  overflow-y: auto;
  padding: var(--space-md);
  color: rgba(255, 255, 255, 0.7);
}

.class-viewer__chat-input {
  display: flex;
  gap: var(--space-sm);
  padding: var(--space-md);
  border-top: 1px solid rgba(255, 255, 255, 0.08);
}

.class-viewer__chat-input .form-input {
  background: rgba(255, 255, 255, 0.06);
  border-color: rgba(255, 255, 255, 0.1);
  color: #FFFFFF;
}

.class-viewer__chat-input .form-input::placeholder {
  color: rgba(255, 255, 255, 0.3);
}

/* ─── Badge Variants ─── */
.badge--live {
  background: var(--color-live);
  color: #FFFFFF;
  animation: pulse-dot 2s ease-in-out infinite;
}

.badge--success {
  background: rgba(16, 185, 129, 0.1);
  color: var(--color-success);
  border: 1px solid rgba(16, 185, 129, 0.2);
}

.badge--error {
  background: rgba(239, 68, 68, 0.1);
  color: var(--color-error);
  border: 1px solid rgba(239, 68, 68, 0.2);
}

.badge--warning {
  background: rgba(245, 158, 11, 0.1);
  color: var(--color-warning);
  border: 1px solid rgba(245, 158, 11, 0.2);
}

.badge--info {
  background: rgba(59, 130, 246, 0.1);
  color: #3B82F6;
  border: 1px solid rgba(59, 130, 246, 0.2);
}

/* ─── Button Variants ─── */
.btn--danger {
  background: var(--color-error);
  color: #FFFFFF;
  border-color: var(--color-error);
}

.btn--danger:hover {
  background: #DC2626;
  transform: translateY(-1px);
}

.btn--success {
  background: var(--color-success);
  color: #FFFFFF;
  border-color: var(--color-success);
}

.btn--success:hover {
  background: #059669;
  transform: translateY(-1px);
}

.btn--secondary {
  background: var(--color-bg-muted);
  color: var(--color-text-primary);
  border: 1.5px solid var(--color-border);
}

.btn--secondary:hover {
  background: var(--color-bg-soft);
  transform: translateY(-1px);
}

.btn--xl {
  padding: 16px 40px;
  font-size: var(--text-lg);
  border-radius: var(--radius-full);
}

/* ─── Tabs (generic) ─── */
.tabs {
  display: flex;
  background: var(--color-bg-muted);
  border-radius: var(--radius-full);
  padding: 4px;
}

.tabs__item {
  flex: 1;
  text-align: center;
  padding: 8px 16px;
  border-radius: var(--radius-full);
  font-family: var(--font-body);
  font-weight: var(--weight-medium);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  cursor: pointer;
  border: none;
  background: transparent;
  transition: all var(--transition-fast);
}

.tabs__item.active {
  background: var(--color-bg);
  color: var(--color-text-primary);
  font-weight: var(--weight-semibold);
  box-shadow: var(--shadow-sm);
}

/* ─── Avatar ─── */
.avatar--xl {
  width: 72px;
  height: 72px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-display);
  font-weight: var(--weight-extrabold);
  font-size: var(--text-2xl);
  flex-shrink: 0;
}

/* ─── Form Helper ─── */
.form-helper {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  margin-top: 4px;
  display: block;
}

/* ─── Utilities ─── */
.text-mono {
  font-family: var(--font-mono);
}

.text-success {
  color: var(--color-success);
}

.text-error {
  color: var(--color-error);
}

.text-bold {
  font-weight: var(--weight-bold);
}

/* ═══════════════════════════════════════════════════════════
   RESPONSIVE — EXAM & CLASS PAGES
   ═══════════════════════════════════════════════════════════ */
@media (max-width: 768px) {
  .exam-body {
    flex-direction: column;
  }

  .exam-nav {
    width: 100%;
    border-right: none;
    border-bottom: 1px solid var(--color-border);
    padding: var(--space-md);
    max-height: 150px;
    overflow-y: auto;
  }

  .exam-nav__grid {
    grid-template-columns: repeat(10, 1fr);
  }

  .exam-question-area {
    padding: var(--space-lg);
  }

  .class-viewer {
    grid-template-columns: 1fr;
    grid-template-rows: 1.5fr 1fr;
    height: 100vh;
  }

  .class-viewer__chat {
    border-left: none;
    border-top: 1px solid rgba(255, 255, 255, 0.08);
  }

  .exam-header {
    padding: var(--space-sm) var(--space-md);
    flex-wrap: wrap;
    gap: var(--space-sm);
  }

  .exam-header__timer {
    font-size: var(--text-lg);
  }
}