/* ==========================================================================
   DeX Learning Centre - Course Teaching Page Stylesheet
   Coursera / LinkedIn Learning Inspired Video Masterclass Experience
   ========================================================================== */

:root {
  --brand-blue-deep: #071b42;
  --brand-blue-dark: #1e40af;
  --brand-blue: #2563eb;
  --brand-blue-light: #3b82f6;
  --brand-blue-soft: #eff6ff;
  --brand-blue-glow: rgba(37, 99, 235, 0.25);
  --brand-yellow: #fbbf24;
  --brand-yellow-dark: #d97706;
  --brand-yellow-soft: #fef3c7;
  --brand-slate-dark: #0f172a;
  --brand-slate-body: #334155;
  --brand-slate-subtle: #64748b;
  --brand-surface: #ffffff;
  --brand-border: rgba(37, 99, 235, 0.14);
  --player-dark: #020617;
  --player-surface: #0b152d;
  --success-emerald: #10b981;
  --success-bg: #ecfdf5;
  --success-border: #a7f3d0;
}

*, *::before, *::after {
  box-sizing: border-box;
}

body {
  margin: 0;
  padding: 0;
  font-family: 'Poppins', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  color: #ffffff;
  background-color: #1e40af !important;
  background-image:
    radial-gradient(circle, rgba(255, 255, 255, 0.08) 1.2px, transparent 1.6px),
    radial-gradient(circle at 18% 18%, rgba(30, 64, 175, 0.5), transparent 45%),
    radial-gradient(circle at 82% 82%, rgba(251, 191, 36, 0.12), transparent 45%),
    linear-gradient(160deg, #1e40af 0%, #1c3d9f 40%, #172554 100%) !important;
  background-position: 0 0, center, center, center !important;
  background-size: 28px 28px, auto, auto, auto !important;
  background-attachment: fixed !important;
  min-height: 100vh;
  overflow-x: hidden;
  position: relative;
}

/* Ambient Yellow Lines Watermark across entire page */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 0;
  background-image: url("/assets/dex-icon-yellow-lines.svg");
  background-repeat: no-repeat;
  background-position: right clamp(-60px, -2vw, 30px) center;
  background-size: clamp(340px, 36vw, 560px) auto;
  opacity: 0.10;
  pointer-events: none;
}

/* ---------------- Text Gradients ---------------- */
.gradient-text {
  background: linear-gradient(135deg, #ffffff 0%, #93c5fd 45%, #fbbf24 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  display: inline;
}

.gradient-gold-text {
  background: linear-gradient(135deg, #fef08a 0%, #fbbf24 50%, #f59e0b 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  display: inline;
}

/* ==========================================================================
   1. UNIFIED MAIN COURSE LAYOUT & MERGED HERO HEADER (FREE & SPACIOUS)
   ========================================================================== */
.course-main-layout {
  max-width: 1360px;
  margin: 0 auto;
  width: 100%;
  padding: clamp(48px, 5.5vw, 76px) clamp(28px, 4.5vw, 64px) 44px;
  display: flex;
  flex-direction: column;
  gap: 36px;
  box-sizing: border-box;
  position: relative;
  z-index: 1;
}

.course-hero-header-block,
.course-hero-section {
  position: relative;
  width: 100%;
  display: flex;
  flex-direction: column;
  gap: 22px;
  background: transparent !important;
  border: none !important;
  box-shadow: none !important;
  padding: 0 !important;
  margin: 0 !important;
}

.course-hero-header-block::before,
.course-hero-section::before {
  display: none !important;
}

.course-hero-inner {
  max-width: 100%;
  margin: 0;
  width: 100%;
  position: relative;
  z-index: 1;
}

.course-hero-breadcrumb-wrap {
  margin-bottom: 22px;
  width: 100%;
}

.course-hero-breadcrumb-wrap dex-breadcrumb,
.course-hero-breadcrumb-wrap dex-breadcrumb .dex-breadcrumb-wrapper,
.course-hero-breadcrumb-wrap dex-breadcrumb .unified-hero-breadcrumb {
  margin-bottom: 0 !important;
  padding: 0 !important;
}

.course-hero-breadcrumb-wrap dex-breadcrumb a {
  color: rgba(255, 255, 255, 0.82) !important;
  transition: color 0.2s ease;
}

.course-hero-breadcrumb-wrap dex-breadcrumb a:hover {
  color: #fbbf24 !important;
}

.course-hero-breadcrumb-wrap dex-breadcrumb a[aria-current="page"] {
  color: #fbbf24 !important;
  font-weight: 700 !important;
}

.course-hero-breadcrumb-wrap dex-breadcrumb svg {
  stroke: rgba(255, 255, 255, 0.45) !important;
}

.course-hero-breadcrumb-wrap dex-breadcrumb a[aria-label="Home"] svg {
  stroke: rgba(255, 255, 255, 0.82) !important;
}

.course-hero-breadcrumb-wrap dex-breadcrumb a[aria-label="Home"]:hover svg {
  stroke: #fbbf24 !important;
}

.course-hero-breadcrumb-wrap dex-breadcrumb ol,
.course-hero-breadcrumb-wrap dex-breadcrumb ul {
  padding-left: 0 !important;
  margin-left: 0 !important;
}

.course-meta-ribbon {
  display: none !important;
}

.course-hero-header-row {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 28px;
  flex-wrap: wrap;
  margin-bottom: 20px;
}

.course-hero-main-col {
  flex: 1 1 680px;
}

.course-hero-badge-strip {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
  margin-bottom: 20px;
}

.course-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 14px;
  border-radius: 9999px;
  font-size: 11.5px;
  font-weight: 700;
  letter-spacing: 0.8px;
  text-transform: uppercase;
  transition: all 0.2s ease;
}

.course-badge.primary {
  background: rgba(255, 255, 255, 0.16);
  color: #ffffff;
  border: 1px solid rgba(255, 255, 255, 0.35);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  box-shadow: 0 4px 14px rgba(0, 0, 0, 0.15);
}

.course-badge.module-pill {
  background: #ffffff;
  color: #1e40af;
  border: 1px solid rgba(255, 255, 255, 0.95);
  box-shadow: 0 4px 14px rgba(0, 0, 0, 0.14);
}

.course-badge.gold-accent {
  background: #fef3c7;
  color: #92400e;
  border: 1px solid rgba(245, 158, 11, 0.4);
  box-shadow: 0 4px 14px rgba(245, 158, 11, 0.18);
}

.course-hero-title {
  font-size: clamp(30px, 3.4vw, 48px);
  font-weight: 800;
  line-height: 1.24;
  color: #ffffff !important;
  margin: 0 0 18px;
  letter-spacing: -0.02em;
  text-shadow: 0 2px 16px rgba(7, 27, 66, 0.4);
}

.course-hero-subtitle {
  font-size: clamp(15.5px, 1.18vw, 18px);
  line-height: 1.72;
  color: rgba(255, 255, 255, 0.90) !important;
  max-width: 880px;
  margin: 0 0 28px;
  font-weight: 400;
}

/* Course Specs / Metadata Ribbon */
.course-meta-ribbon {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
}

.course-meta-item {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 12.5px;
  font-weight: 600;
  color: #334155;
  padding: 4px 0;
}

.course-meta-item svg {
  width: 15px;
  height: 15px;
  color: #2563eb;
  flex-shrink: 0;
}

.course-meta-item.rating {
  color: #b45309;
}

.course-meta-item.rating svg {
  color: #f59e0b;
  fill: #f59e0b;
}

/* Hero Right Actions Box */
.course-hero-actions-col {
  display: flex;
  flex-direction: column;
  gap: 10px;
  align-items: flex-end;
}

.hero-action-btn-group {
  display: flex;
  align-items: center;
  gap: 8px;
}

.hero-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 20px;
  border-radius: 12px;
  font-size: 13px;
  font-weight: 700;
  cursor: pointer;
  transition: all 0.25s cubic-bezier(0.16, 1, 0.3, 1);
  text-decoration: none;
  border: none;
}

.hero-btn.primary {
  background: #ffffff !important;
  color: #1e40af !important;
  border: 1px solid rgba(255, 255, 255, 0.9) !important;
  box-shadow: 0 4px 18px rgba(0, 0, 0, 0.25) !important;
}

.hero-btn.primary:hover {
  transform: translateY(-2px);
  background: #eff6ff !important;
  color: #1d4ed8 !important;
  box-shadow: 0 8px 26px rgba(0, 0, 0, 0.35) !important;
}

.hero-btn.outline {
  background: rgba(255, 255, 255, 0.15);
  color: #ffffff;
  border: 1px solid rgba(255, 255, 255, 0.4);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
  backdrop-filter: blur(10px);
}

.hero-btn.outline:hover {
  background: rgba(255, 255, 255, 0.25);
  border-color: #ffffff;
  color: #ffffff;
}

/* ---------------- Dynamic Global Progress Bar in Hero (Spacious 3D Glassmorphic) ---------------- */
.course-hero-progress-card {
  background: rgba(255, 255, 255, 0.97);
  backdrop-filter: blur(24px) saturate(180%);
  -webkit-backdrop-filter: blur(24px) saturate(180%);
  border-radius: 20px;
  border: 1px solid rgba(255, 255, 255, 0.95);
  padding: 22px 30px;
  box-shadow: 
    0 22px 50px -12px rgba(7, 27, 66, 0.4),
    0 6px 18px rgba(0, 0, 0, 0.08),
    inset 0 1px 1px rgba(255, 255, 255, 1);
  margin-top: 24px;
  margin-bottom: 32px;
  display: flex;
  flex-direction: column;
  gap: 16px;
  position: relative;
  overflow: visible;
  transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

.course-hero-progress-card:hover {
  transform: translateY(-2px);
  box-shadow: 
    0 26px 56px -10px rgba(7, 27, 66, 0.45),
    0 10px 24px rgba(0, 0, 0, 0.1),
    inset 0 1px 1px rgba(255, 255, 255, 1);
}

.progress-header-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 14px;
}

.progress-title-wrap {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}

.progress-icon {
  width: 21px;
  height: 21px;
  color: #2563eb;
  filter: drop-shadow(0 2px 4px rgba(37, 99, 235, 0.35));
}

.progress-title-text {
  font-size: 14.5px;
  font-weight: 800;
  color: #0f172a;
  letter-spacing: -0.01em;
}

.progress-stat-pill {
  font-size: 12px;
  font-weight: 700;
  color: #1e40af;
  background: #eff6ff;
  padding: 5px 14px;
  border-radius: 9999px;
  border: 1px solid rgba(37, 99, 235, 0.25);
  box-shadow: 0 2px 8px rgba(37, 99, 235, 0.12), inset 0 1px 0 #ffffff;
  display: inline-flex;
  align-items: center;
  gap: 5px;
  cursor: pointer;
  user-select: none;
  transition: all 0.25s ease;
  font-family: inherit;
}

.progress-stat-pill:hover {
  background: #dbeafe;
  transform: scale(1.04);
  box-shadow: 0 4px 14px rgba(37, 99, 235, 0.22);
}

.progress-next-up-indicator {
  font-size: 13px;
  font-weight: 600;
  color: #64748b;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.progress-next-up-indicator strong {
  color: #1e40af;
  font-weight: 800;
}

.progress-bar-track {
  width: 100%;
  height: 12px;
  background: #e2e8f0;
  border-radius: 9999px;
  overflow: hidden !important;
  position: relative;
  box-shadow: inset 0 2px 4px rgba(15, 23, 42, 0.12), 0 1px 0 rgba(255, 255, 255, 0.95);
  cursor: pointer;
}

.progress-bar-fill {
  height: 100%;
  width: 11%;
  background: linear-gradient(90deg, #2563eb 0%, #3b82f6 50%, #fbbf24 100%);
  border-radius: 9999px;
  overflow: hidden !important;
  transition: width 0.65s cubic-bezier(0.34, 1.56, 0.64, 1);
  box-shadow: inset 0 1px 1px rgba(255, 255, 255, 0.7);
  position: relative;
  z-index: 1;
}

.progress-bar-fill::after {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: linear-gradient(
    90deg,
    transparent 0%,
    rgba(255, 255, 255, 0.6) 50%,
    transparent 100%
  );
  animation: shimmerProgress 2.2s infinite ease-in-out;
  border-radius: inherit;
}

@keyframes shimmerProgress {
  0% { transform: translateX(-100%); }
  100% { transform: translateX(200%); }
}

/* Hide milestone numbers completely as per user request */
.progress-milestones-row {
  display: none !important;
}

.milestone-dot {
  display: none !important;
}

/* ==========================================================================
   2. MAIN COURSE TEACHING STAGE (Bigger Video Player Left, Transcript Right)
   ========================================================================== */
/* 2-Column Stage Row: Prominent Larger Video Left, Transcript Right (Matching Height) */
.course-stage-row {
  display: grid;
  grid-template-columns: minmax(0, 1.8fr) minmax(320px, 0.95fr);
  gap: 28px;
  align-items: stretch;
  width: 100%;
}

/* ---------------- LEFT STAGE: Video & Sub-Action Bar ---------------- */
.course-player-stage {
  min-width: 0;
  display: flex;
  flex-direction: column;
  gap: 14px;
  height: 100%;
}

/* The Studio Player Frame */
.player-window-card {
  background: #020617;
  border-radius: 20px;
  overflow: hidden;
  box-shadow:
    0 24px 60px -10px rgba(7, 27, 66, 0.45),
    0 0 0 1px rgba(255, 255, 255, 0.12),
    0 0 35px rgba(37, 99, 235, 0.18);
  border: 1px solid rgba(255, 255, 255, 0.15);
  display: flex;
  flex-direction: column;
  transition: all 0.35s ease;
}

.player-window-card.theater-mode {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  width: 100vw;
  height: 100vh;
  z-index: 99999;
  border-radius: 0;
  margin: 0;
}

.player-window-card.theater-mode .player-host-box {
  flex: 1;
  aspect-ratio: unset;
  height: calc(100vh - 42px);
}

/* Browser / Studio Top Frame Bar */
.player-studio-topbar {
  height: 42px;
  background: rgba(11, 21, 45, 0.95);
  border-bottom: 1px solid rgba(255, 255, 255, 0.12);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 16px;
  box-sizing: border-box;
  user-select: none;
}

.studio-dots {
  display: inline-flex;
  align-items: center;
  gap: 7px;
}

.studio-dot {
  width: 11px;
  height: 11px;
  border-radius: 50%;
  display: inline-block;
}

.studio-dot.red { background: #ff5f56; box-shadow: 0 0 6px rgba(255, 95, 86, 0.5); }
.studio-dot.yellow { background: #ffbd2e; box-shadow: 0 0 6px rgba(255, 189, 46, 0.5); }
.studio-dot.green { background: #27c93f; box-shadow: 0 0 6px rgba(39, 201, 63, 0.5); }

.studio-lesson-pill {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: rgba(255, 255, 255, 0.1);
  border: 1px solid rgba(255, 255, 255, 0.16);
  padding: 4px 14px;
  border-radius: 6px;
  font-size: 12px;
  font-weight: 600;
  color: rgba(255, 255, 255, 0.92);
  max-width: 60%;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.studio-lesson-pill svg {
  width: 13px;
  height: 13px;
  color: #fbbf24;
  flex-shrink: 0;
}

.studio-right-badges {
  display: flex;
  align-items: center;
  gap: 8px;
}

.studio-hd-badge {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  font-size: 10px;
  font-weight: 700;
  color: #fbbf24;
  background: rgba(251, 191, 36, 0.14);
  border: 1px solid rgba(251, 191, 36, 0.35);
  padding: 2px 8px;
  border-radius: 9999px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.studio-theater-btn {
  background: transparent;
  border: none;
  color: rgba(255, 255, 255, 0.7);
  width: 28px;
  height: 28px;
  border-radius: 6px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all 0.2s ease;
}

.studio-theater-btn:hover {
  background: rgba(255, 255, 255, 0.15);
  color: #ffffff;
}

.studio-theater-btn svg {
  width: 14px;
  height: 14px;
}

/* Video Player Host Container */
.player-host-box {
  width: 100%;
  aspect-ratio: 16 / 9;
  background: #000000;
  position: relative;
  overflow: hidden;
}

.player-host-box dex-video-player {
  width: 100%;
  height: 100%;
  display: block;
}

.player-host-box dex-video-player .dex-emulator-topbar {
  display: none !important;
}

.player-host-box dex-video-player .dex-emulator-viewport {
  height: 100% !important;
}

/* ---------------- Active Lesson Quick Action Bar (3D Glassmorphic) ---------------- */
.player-sub-action-bar {
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: blur(18px) saturate(180%);
  -webkit-backdrop-filter: blur(18px) saturate(180%);
  border-radius: 18px;
  border: 1px solid rgba(255, 255, 255, 0.95);
  box-shadow: 
    0 12px 30px -8px rgba(15, 23, 42, 0.08),
    0 2px 8px rgba(37, 99, 235, 0.04),
    inset 0 1px 1px rgba(255, 255, 255, 1);
  padding: 12px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}

.sub-bar-left,
.sub-bar-right {
  display: flex;
  align-items: center;
  gap: 10px;
}

/* Previous / Next Lesson Navigation Buttons */
.nav-lesson-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 16px;
  border-radius: 12px;
  font-size: 12.5px;
  font-weight: 600;
  color: #1e40af;
  background: rgba(239, 246, 255, 0.95);
  border: 1px solid rgba(37, 99, 235, 0.22);
  box-shadow: 0 2px 6px rgba(37, 99, 235, 0.06), inset 0 1px 0 #ffffff;
  text-decoration: none;
  cursor: pointer;
  transition: all 0.25s cubic-bezier(0.16, 1, 0.3, 1);
}

.nav-lesson-btn:hover:not(.disabled) {
  background: #dbeafe;
  color: #1d4ed8;
  transform: translateY(-2px);
  box-shadow: 0 6px 14px rgba(37, 99, 235, 0.16), inset 0 1px 0 #ffffff;
}

.nav-lesson-btn.disabled {
  opacity: 0.45;
  pointer-events: none;
  cursor: not-allowed;
  border-color: #cbd5e1;
  color: #94a3b8;
  background: #f1f5f9;
}

.nav-lesson-btn svg {
  width: 14px;
  height: 14px;
}

/* Mark as Complete Interactive Toggle */
.btn-toggle-completion {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 18px;
  border-radius: 12px;
  font-size: 13px;
  font-weight: 700;
  cursor: pointer;
  transition: all 0.25s cubic-bezier(0.16, 1, 0.3, 1);
  border: 1.5px solid rgba(37, 99, 235, 0.4);
  background: #ffffff;
  color: #2563eb;
  box-shadow: 0 2px 8px rgba(37, 99, 235, 0.08), inset 0 1px 0 #ffffff;
}

.btn-toggle-completion:hover {
  background: #eff6ff;
  border-color: #2563eb;
  transform: translateY(-2px);
  box-shadow: 0 6px 16px rgba(37, 99, 235, 0.18), inset 0 1px 0 #ffffff;
}

.btn-toggle-completion.completed {
  background: linear-gradient(135deg, #10b981 0%, #059669 100%);
  border-color: #047857;
  color: #ffffff;
  box-shadow: 0 4px 16px rgba(16, 185, 129, 0.35), inset 0 1px 0 rgba(255, 255, 255, 0.4);
}

.btn-toggle-completion.completed:hover {
  background: linear-gradient(135deg, #059669 0%, #047857 100%);
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(16, 185, 129, 0.45);
}

.btn-toggle-completion svg {
  width: 16px;
  height: 16px;
  transition: transform 0.2s ease;
}

.btn-toggle-completion.completed svg {
  transform: scale(1.15);
}

/* Autoplay Next Toggle Switch */
.autoplay-toggle-wrap {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 12px;
  font-weight: 600;
  color: #475569;
  user-select: none;
}

.autoplay-switch {
  position: relative;
  display: inline-block;
  width: 36px;
  height: 20px;
}

.autoplay-switch input {
  opacity: 0;
  width: 0;
  height: 0;
}

.slider-switch {
  position: absolute;
  cursor: pointer;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: #cbd5e1;
  transition: .3s cubic-bezier(0.16, 1, 0.3, 1);
  border-radius: 20px;
}

.slider-switch:before {
  position: absolute;
  content: "";
  height: 14px;
  width: 14px;
  left: 3px;
  bottom: 3px;
  background-color: white;
  transition: .3s cubic-bezier(0.16, 1, 0.3, 1);
  border-radius: 50%;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.2);
}

input:checked + .slider-switch {
  background-color: #2563eb;
}

input:checked + .slider-switch:before {
  transform: translateX(16px);
}

/* ---------------- Interactive Teaching Tab Navigation (Seamless Blue Stage Flow) ---------------- */
.course-description-blue-section,
.course-description-section {
  width: 100%;
  position: relative;
  overflow: visible;
  padding: 16px 0 clamp(68px, 8vw, 104px);
  margin: 0;
  background: transparent !important;
  border: none !important;
  box-shadow: none !important;
  border-radius: 0 !important;
  display: block;
}

/* Watermark is already active on body::before */
.course-description-blue-section::before,
.course-description-section::before {
  display: none !important;
}

.course-description-container {
  width: 100%;
  max-width: 1240px;
  margin: 0 auto;
  padding: 0 clamp(20px, 3.5vw, 40px);
  position: relative;
  z-index: 2;
  box-sizing: border-box;
}

/* Blue Stage Header */
.description-blue-header {
  text-align: center;
  max-width: 760px;
  margin: 0 auto 36px;
  color: #ffffff;
}

.description-badge-pill {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 18px;
  border-radius: 9999px;
  background: rgba(255, 255, 255, 0.14);
  border: 1px solid rgba(255, 255, 255, 0.28);
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.15), inset 0 1px 0 rgba(255, 255, 255, 0.3);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  color: #fbbf24;
  font-size: 11.5px;
  font-weight: 700;
  letter-spacing: 1.1px;
  text-transform: uppercase;
  margin-bottom: 14px;
}

.description-blue-title {
  font-size: clamp(26px, 3.2vw, 40px);
  font-weight: 800;
  line-height: 1.2;
  color: #ffffff;
  margin: 0 0 12px;
  letter-spacing: -0.02em;
}

.description-blue-subtitle {
  font-size: 14.5px;
  color: rgba(255, 255, 255, 0.85);
  margin: 0 auto;
  line-height: 1.6;
  max-width: 640px;
}

/* 3D Glassmorphic White Description Card */
.course-tabs-container {
  width: 100%;
  max-width: 1140px;
  margin: 0 auto;
  background: #ffffff;
  border-radius: 24px;
  border: 1px solid rgba(255, 255, 255, 0.85);
  box-shadow: 
    0 32px 75px -15px rgba(7, 27, 66, 0.5),
    0 16px 36px -8px rgba(0, 0, 0, 0.3),
    inset 0 1px 1px rgba(255, 255, 255, 1);
  overflow: hidden;
  position: relative;
  z-index: 2;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.course-tabs-container:hover {
  box-shadow: 
    0 36px 85px -15px rgba(7, 27, 66, 0.55),
    0 18px 40px -8px rgba(0, 0, 0, 0.35),
    inset 0 1px 1px rgba(255, 255, 255, 1);
}

.course-tabs-nav {
  display: flex;
  align-items: center;
  justify-content: center;
  border-bottom: 1px solid rgba(226, 232, 240, 0.9);
  background: #f8fafc;
  padding: 10px 18px;
  overflow-x: auto;
  scrollbar-width: none;
  gap: 10px;
}

.course-tabs-nav::-webkit-scrollbar {
  display: none;
}

.course-tab-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 20px;
  font-size: 13.5px;
  font-weight: 600;
  color: #64748b;
  background: transparent;
  border: 1px solid transparent;
  border-radius: 12px;
  cursor: pointer;
  transition: all 0.22s cubic-bezier(0.16, 1, 0.3, 1);
  white-space: nowrap;
}

.course-tab-btn:hover {
  color: #1e40af;
  background: rgba(37, 99, 235, 0.06);
}

.course-tab-btn.active {
  color: #1e40af;
  background: #ffffff;
  border-color: rgba(37, 99, 235, 0.2);
  box-shadow: 0 4px 14px rgba(15, 23, 42, 0.08), inset 0 1px 0 #ffffff;
  font-weight: 700;
}

.course-tab-btn svg {
  width: 16px;
  height: 16px;
  flex-shrink: 0;
}

.course-tab-badge {
  font-size: 10px;
  font-weight: 700;
  background: #eff6ff;
  color: #1e40af;
  padding: 2px 7px;
  border-radius: 9999px;
  border: 1px solid rgba(37, 99, 235, 0.2);
}

/* Tab Content Panels */
.course-tab-content-area {
  padding: clamp(24px, 3.5vw, 42px);
}

.course-tab-panel {
  display: none;
}

.course-tab-panel.active {
  display: block;
  animation: fadeInTab 0.3s ease-out;
}

@keyframes fadeInTab {
  from { opacity: 0; transform: translateY(6px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ---------------- TAB: OVERVIEW & NOTES ---------------- */
.lesson-overview-header {
  margin-bottom: 28px;
  padding-bottom: 20px;
  border-bottom: 1px solid #e2e8f0;
}

.lesson-topic-tag {
  display: inline-block;
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.8px;
  color: #1e40af;
  background: rgba(37, 99, 235, 0.08);
  padding: 3px 10px;
  border-radius: 6px;
  margin-bottom: 10px;
}

.lesson-main-heading {
  font-size: clamp(22px, 2.2vw, 28px);
  font-weight: 800;
  color: #0f172a;
  line-height: 1.3;
  margin: 0 0 10px;
}

.lesson-lead-paragraph {
  font-size: 15.5px;
  line-height: 1.65;
  color: #475569;
  font-weight: 400;
  margin: 0;
}

/* Callout Box */
.lesson-callout-box {
  background: linear-gradient(135deg, rgba(37, 99, 235, 0.06) 0%, rgba(251, 191, 36, 0.08) 100%);
  border-left: 4px solid #2563eb;
  padding: 18px 22px;
  border-radius: 0 14px 14px 0;
  margin: 24px 0;
}

.lesson-callout-box h4 {
  font-size: 14.5px;
  font-weight: 700;
  color: #1e40af;
  margin: 0 0 6px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.lesson-callout-box p {
  font-size: 13.5px;
  line-height: 1.6;
  color: #334155;
  margin: 0;
}

/* 3-Card Takeaways Grid */
.takeaways-cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 16px;
  margin: 24px 0 32px;
}

.takeaway-card {
  background: #f8fafc;
  border: 1px solid rgba(37, 99, 235, 0.12);
  border-radius: 14px;
  padding: 18px;
  transition: all 0.25s ease;
}

.takeaway-card:hover {
  transform: translateY(-2px);
  border-color: rgba(37, 99, 235, 0.35);
  box-shadow: 0 6px 18px rgba(37, 99, 235, 0.08);
  background: #ffffff;
}

.takeaway-card-icon {
  width: 36px;
  height: 36px;
  border-radius: 10px;
  background: #eff6ff;
  border: 1px solid rgba(37, 99, 235, 0.2);
  color: #2563eb;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 12px;
}

.takeaway-card h4 {
  font-size: 14px;
  font-weight: 700;
  color: #0f172a;
  margin: 0 0 6px;
}

.takeaway-card p {
  font-size: 12.5px;
  line-height: 1.55;
  color: #64748b;
  margin: 0;
}

/* Technical Article Content Styles */
.lesson-article-body h2 {
  font-size: clamp(17px, 1.8vw, 22px);
  font-weight: 700;
  color: #0f172a;
  margin: 32px 0 14px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.lesson-article-body h2::before {
  content: "";
  display: inline-block;
  width: 4px;
  height: 20px;
  background: #2563eb;
  border-radius: 2px;
}

.lesson-article-body p {
  font-size: 14.5px;
  line-height: 1.75;
  color: #334155;
  margin-bottom: 18px;
}

.lesson-article-body ul {
  margin: 0 0 22px 20px;
  padding: 0;
}

.lesson-article-body li {
  font-size: 14px;
  line-height: 1.7;
  color: #334155;
  margin-bottom: 8px;
}

/* Image / Diagram Showcase */
.image-showcase-container {
  border-radius: 14px;
  overflow: hidden;
  border: 1px solid rgba(226, 232, 240, 0.95);
  box-shadow: 0 10px 24px -4px rgba(15, 23, 42, 0.08);
  margin: 28px 0;
  background: #f8fafc;
}

.image-showcase-container img {
  width: 100%;
  height: auto;
  display: block;
  object-fit: cover;
}

.image-caption {
  padding: 10px 16px;
  background: #ffffff;
  border-top: 1px solid #e2e8f0;
  font-size: 12px;
  color: #64748b;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

/* ---------------- TAB: RESOURCES & DOWNLOADS ---------------- */
.resources-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 18px;
}

.resource-download-card {
  background: #ffffff;
  border: 1px solid rgba(37, 99, 235, 0.16);
  border-radius: 14px;
  padding: 20px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  box-shadow: 0 4px 14px rgba(15, 23, 42, 0.04);
  transition: all 0.25s ease;
}

.resource-download-card:hover {
  transform: translateY(-2px);
  border-color: #2563eb;
  box-shadow: 0 8px 24px rgba(37, 99, 235, 0.12);
}

.resource-card-top {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  margin-bottom: 16px;
}

.resource-icon-badge {
  width: 42px;
  height: 42px;
  border-radius: 10px;
  background: #eff6ff;
  border: 1px solid rgba(37, 99, 235, 0.2);
  color: #2563eb;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.resource-card-info h4 {
  font-size: 14px;
  font-weight: 700;
  color: #0f172a;
  margin: 0 0 4px;
}

.resource-card-info p {
  font-size: 12px;
  color: #64748b;
  margin: 0;
}

.resource-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 8px 14px;
  border-radius: 8px;
  font-size: 12px;
  font-weight: 700;
  color: #1e40af;
  background: #eff6ff;
  border: 1px solid rgba(37, 99, 235, 0.25);
  text-decoration: none;
  cursor: pointer;
  transition: all 0.2s ease;
}

.resource-btn:hover {
  background: #2563eb;
  color: #ffffff;
  border-color: #2563eb;
}

/* ---------------- TAB: MY NOTES ---------------- */
.notes-workspace {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.notes-textarea {
  width: 100%;
  min-height: 220px;
  padding: 16px;
  border-radius: 12px;
  border: 1px solid #cbd5e1;
  font-size: 14px;
  line-height: 1.6;
  color: #1e293b;
  resize: vertical;
  background: #ffffff;
  outline: none;
  transition: border-color 0.2s ease;
}

.notes-textarea:focus {
  border-color: #2563eb;
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.12);
}

.notes-footer-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 10px;
}

.notes-status-text {
  font-size: 12px;
  color: #10b981;
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: 5px;
}

.notes-actions {
  display: flex;
  gap: 8px;
}

.notes-btn {
  padding: 6px 14px;
  border-radius: 8px;
  font-size: 12px;
  font-weight: 600;
  border: 1px solid #cbd5e1;
  background: #ffffff;
  color: #334155;
  cursor: pointer;
  transition: all 0.2s ease;
}

.notes-btn:hover {
  background: #f1f5f9;
  border-color: #94a3b8;
}

/* ---------------- TAB: KNOWLEDGE CHECK (QUIZ) ---------------- */
.quiz-container {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.quiz-question-box {
  background: #f8fafc;
  border: 1px solid rgba(37, 99, 235, 0.14);
  border-radius: 14px;
  padding: 20px;
}

.quiz-question-num {
  font-size: 11px;
  font-weight: 700;
  color: #2563eb;
  text-transform: uppercase;
  letter-spacing: 0.8px;
  margin-bottom: 6px;
}

.quiz-question-text {
  font-size: 15px;
  font-weight: 700;
  color: #0f172a;
  margin: 0 0 16px;
}

.quiz-options-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.quiz-option-label {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 16px;
  background: #ffffff;
  border: 1px solid #e2e8f0;
  border-radius: 10px;
  cursor: pointer;
  font-size: 13.5px;
  color: #334155;
  transition: all 0.2s ease;
  user-select: none;
}

.quiz-option-label:hover {
  background: #eff6ff;
  border-color: rgba(37, 99, 235, 0.35);
}

.quiz-option-label input[type="radio"] {
  accent-color: #2563eb;
  width: 16px;
  height: 16px;
}

.quiz-option-label.correct {
  background: #ecfdf5 !important;
  border-color: #10b981 !important;
  color: #065f46 !important;
  font-weight: 600;
}

.quiz-option-label.incorrect {
  background: #fef2f2 !important;
  border-color: #ef4444 !important;
  color: #991b1b !important;
}

.quiz-feedback-box {
  margin-top: 14px;
  padding: 12px 16px;
  border-radius: 8px;
  font-size: 13px;
  line-height: 1.5;
  display: none;
}

.quiz-feedback-box.show {
  display: block;
}

.quiz-feedback-box.success {
  background: #ecfdf5;
  color: #065f46;
  border-left: 3px solid #10b981;
}

.quiz-feedback-box.error {
  background: #fef2f2;
  color: #991b1b;
  border-left: 3px solid #ef4444;
}

.quiz-submit-btn {
  margin-top: 10px;
  align-self: flex-start;
  padding: 8px 18px;
  border-radius: 8px;
  font-size: 13px;
  font-weight: 700;
  background: #2563eb;
  color: #ffffff;
  border: none;
  cursor: pointer;
  transition: all 0.2s ease;
}

.quiz-submit-btn:hover {
  background: #1d4ed8;
}

/* ==========================================================================
   3. RIGHT SIDEBAR: INTERACTIVE LIVE TRANSCRIPTION & CHAPTERS
   ========================================================================== */
.transcript-sidebar-card {
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: blur(20px) saturate(180%);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  border-radius: 20px;
  border: 1px solid rgba(255, 255, 255, 0.95);
  box-shadow: 
    0 24px 55px -12px rgba(37, 99, 235, 0.14),
    0 6px 18px rgba(15, 23, 42, 0.04),
    inset 0 1px 1px rgba(255, 255, 255, 1);
  padding: 18px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  height: 100%;
  max-height: 100%;
  min-height: 0;
  box-sizing: border-box;
  overflow: hidden;
  position: relative;
  top: auto;
  transition: all 0.3s ease;
}

.transcript-header-box {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-bottom: 12px;
  border-bottom: 1px solid #e2e8f0;
}

.transcript-title-wrap {
  display: flex;
  align-items: center;
  gap: 10px;
}

.transcript-icon {
  width: 22px;
  height: 22px;
  color: #2563eb;
  flex-shrink: 0;
}

.transcript-title-wrap h3 {
  font-size: 15px;
  font-weight: 800;
  color: #0f172a;
  margin: 0;
  line-height: 1.2;
}

.transcript-subtitle {
  display: none !important;
}

.transcript-controls-row {
  display: flex;
  align-items: center;
  gap: 8px;
}

.transcript-autoscroll-toggle {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  font-size: 11px;
  font-weight: 600;
  color: #64748b;
  cursor: pointer;
  user-select: none;
}

.transcript-autoscroll-toggle input {
  accent-color: #2563eb;
  cursor: pointer;
}

.transcript-action-btn {
  background: #f1f5f9;
  border: 1px solid #cbd5e1;
  border-radius: 6px;
  padding: 4px 8px;
  font-size: 11px;
  font-weight: 600;
  color: #334155;
  display: inline-flex;
  align-items: center;
  gap: 4px;
  cursor: pointer;
  transition: all 0.2s ease;
}

.transcript-action-btn:hover {
  background: #eff6ff;
  border-color: #2563eb;
  color: #1e40af;
}

/* Quick Chapter Navigation Pills (Hidden as requested) */
.transcript-chapters-bar {
  display: none !important;
}

/* Search within Transcript (Hidden as requested) */
.transcript-search-wrap {
  display: none !important;
}

/* Transcript Feed */
.transcript-feed {
  flex: 1 1 0;
  min-height: 0;
  overflow-y: auto;
  overflow-x: hidden;
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding-right: 4px;
  scrollbar-width: thin;
  scrollbar-color: rgba(37, 99, 235, 0.25) transparent;
}

.transcript-feed::-webkit-scrollbar {
  width: 5px;
}

.transcript-feed::-webkit-scrollbar-thumb {
  background: rgba(37, 99, 235, 0.2);
  border-radius: 4px;
}

.transcript-line-item {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  padding: 11px 13px;
  border-radius: 10px;
  background: #f8fafc;
  border: 1px solid transparent;
  cursor: default !important;
  user-select: text;
  pointer-events: auto;
  transition: background 0.2s ease, border-color 0.2s ease;
}

.transcript-line-item:hover {
  background: #f8fafc;
  border-color: transparent;
  transform: none !important;
}

.transcript-line-item.active {
  background: #eff6ff;
  border-color: #2563eb;
  box-shadow: 0 4px 14px rgba(37, 99, 235, 0.12);
}

.transcript-time-badge {
  font-size: 11px;
  font-weight: 700;
  color: #2563eb;
  background: rgba(37, 99, 235, 0.1);
  padding: 2px 7px;
  border-radius: 5px;
  flex-shrink: 0;
  letter-spacing: 0.3px;
  margin-top: 1px;
}

.transcript-line-item.active .transcript-time-badge {
  background: #2563eb;
  color: #ffffff;
}

.transcript-text-col {
  flex: 1;
  min-width: 0;
}

.transcript-speaker-row {
  display: flex;
  align-items: center;
  gap: 6px;
  margin-bottom: 2px;
}

.transcript-speaker {
  font-size: 11px;
  font-weight: 700;
  color: #0f172a;
}

.transcript-chapter-tag {
  font-size: 9.5px;
  font-weight: 600;
  color: #64748b;
  background: #e2e8f0;
  padding: 1px 5px;
  border-radius: 3px;
}

.transcript-sentence {
  font-size: 12.5px;
  line-height: 1.55;
  color: #334155;
}

.transcript-line-item.active .transcript-sentence {
  color: #0f172a;
  font-weight: 600;
}

/* ==========================================================================
   4. EPISODES & CURRICULUM SECTION (Placed below the player)
   ========================================================================== */
.course-episodes-section {
  width: 100%;
  position: relative;
  background: linear-gradient(180deg, #ffffff 0%, #f8fbff 50%, #eff6ff 100%);
  padding: clamp(48px, 6vw, 72px) 20px clamp(56px, 7vw, 84px);
  border-top: 1px solid rgba(37, 99, 235, 0.12);
}

.episodes-section-inner {
  max-width: 1400px;
  margin: 0 auto;
}

.episodes-section-header {
  text-align: center;
  max-width: 780px;
  margin: 0 auto 40px;
}

.episodes-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 14px;
  border-radius: 9999px;
  background: #eff6ff;
  border: 1px solid rgba(37, 99, 235, 0.22);
  color: #1e40af;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.8px;
  text-transform: uppercase;
  margin-bottom: 12px;
}

.episodes-title {
  font-size: clamp(26px, 3.2vw, 40px);
  font-weight: 800;
  color: #0f172a;
  line-height: 1.2;
  margin: 0 0 12px;
  letter-spacing: -0.02em;
}

.episodes-subtitle {
  font-size: clamp(14px, 1.1vw, 16px);
  line-height: 1.6;
  color: #475569;
  margin: 0 auto;
}

/* 3-Column Episodes Grid */
.episodes-grid-cards {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(360px, 1fr));
  gap: 24px;
  margin-bottom: 48px;
}

.episode-card {
  background: #ffffff;
  border-radius: 18px;
  border: 1px solid rgba(226, 232, 240, 0.95);
  box-shadow: 0 8px 24px -4px rgba(15, 23, 42, 0.05);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  text-decoration: none;
  color: inherit;
  transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
  position: relative;
}

.episode-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 16px 36px -4px rgba(37, 99, 235, 0.14);
  border-color: rgba(37, 99, 235, 0.35);
}

.episode-card.current {
  border: 2px solid #2563eb;
  box-shadow: 0 12px 32px rgba(37, 99, 235, 0.16);
}

.episode-card-media {
  width: 100%;
  aspect-ratio: 16 / 9;
  background: #020617;
  position: relative;
  overflow: hidden;
}

.episode-card-media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
  transition: transform 0.4s ease;
}

.episode-card:hover .episode-card-media img {
  transform: scale(1.04);
}

.episode-card-badge {
  position: absolute;
  top: 10px;
  left: 10px;
  padding: 3px 9px;
  border-radius: 6px;
  font-size: 10.5px;
  font-weight: 700;
  letter-spacing: 0.5px;
  text-transform: uppercase;
  background: rgba(15, 23, 42, 0.85);
  color: #ffffff;
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
}

.episode-card-duration {
  position: absolute;
  bottom: 10px;
  right: 10px;
  background: rgba(0, 0, 0, 0.8);
  color: #ffffff;
  padding: 2px 7px;
  border-radius: 4px;
  font-size: 11px;
  font-weight: 600;
}

.episode-card-now-playing {
  position: absolute;
  top: 10px;
  right: 10px;
  background: #2563eb;
  color: #ffffff;
  padding: 3px 10px;
  border-radius: 9999px;
  font-size: 10px;
  font-weight: 700;
  display: flex;
  align-items: center;
  gap: 5px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  box-shadow: 0 2px 8px rgba(37, 99, 235, 0.4);
}

.episode-card-body {
  padding: 18px 20px;
  display: flex;
  flex-direction: column;
  flex: 1;
  justify-content: space-between;
}

.episode-card-top-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 8px;
}

.episode-card-num {
  font-size: 11px;
  font-weight: 700;
  color: #2563eb;
  text-transform: uppercase;
  letter-spacing: 0.6px;
}

.episode-card-check {
  width: 20px;
  height: 20px;
  border-radius: 50%;
  border: 1.5px solid #cbd5e1;
  background: #ffffff;
  display: flex;
  align-items: center;
  justify-content: center;
  color: transparent;
  transition: all 0.2s ease;
  cursor: pointer;
}

.episode-card-check.checked {
  background: #10b981;
  border-color: #059669;
  color: #ffffff;
}

.episode-card-check svg {
  width: 12px;
  height: 12px;
  stroke-width: 3;
}

.episode-card-title {
  font-size: 15px;
  font-weight: 700;
  color: #0f172a;
  line-height: 1.35;
  margin: 0 0 8px;
}

.episode-card-lead {
  font-size: 12.5px;
  line-height: 1.55;
  color: #64748b;
  margin: 0 0 16px;
  flex: 1;
}

.episode-card-action-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 12px;
  border-top: 1px solid #f1f5f9;
}

.episode-card-btn-label {
  font-size: 12px;
  font-weight: 700;
  color: #1e40af;
  display: inline-flex;
  align-items: center;
  gap: 5px;
}

.episode-card:hover .episode-card-btn-label {
  color: #2563eb;
}

.episode-card:hover .episode-card-btn-label svg {
  transform: translateX(3px);
}

.episode-card-btn-label svg {
  width: 14px;
  height: 14px;
  transition: transform 0.2s ease;
}

/* Bottom Credentials & Certificate Banner */
.episodes-bottom-credentials-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
}

/* Certificate Preview Box */
.bottom-certificate-box {
  background: linear-gradient(135deg, #071b42 0%, #1e40af 100%);
  border-radius: 20px;
  padding: 24px;
  color: #ffffff;
  position: relative;
  overflow: hidden;
  box-shadow: 0 14px 34px rgba(7, 27, 66, 0.25);
  border: 1px solid rgba(251, 191, 36, 0.35);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.bottom-certificate-box::before {
  content: "";
  position: absolute;
  top: -30px;
  right: -30px;
  width: 180px;
  height: 180px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(251, 191, 36, 0.2) 0%, transparent 70%);
  pointer-events: none;
}

.bottom-cert-top {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 12px;
}

.bottom-cert-icon {
  width: 38px;
  height: 38px;
  color: #fbbf24;
  flex-shrink: 0;
}

.bottom-cert-info h3 {
  font-size: 16px;
  font-weight: 800;
  color: #ffffff;
  margin: 0 0 2px;
}

.bottom-cert-info span {
  font-size: 11.5px;
  color: #fbbf24;
  font-weight: 700;
}

.bottom-cert-desc {
  font-size: 13px;
  line-height: 1.6;
  color: rgba(255, 255, 255, 0.88);
  margin: 0 0 18px;
}

/* Bottom Instructor Council Box */
.bottom-council-box {
  background: #ffffff;
  border-radius: 20px;
  padding: 24px;
  border: 1px solid rgba(37, 99, 235, 0.18);
  box-shadow: 0 8px 24px rgba(15, 23, 42, 0.05);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.bottom-council-top {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 12px;
}

.bottom-council-avatar {
  width: 46px;
  height: 46px;
  border-radius: 50%;
  background: #eff6ff;
  border: 1.5px solid rgba(37, 99, 235, 0.3);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #1e40af;
  flex-shrink: 0;
}

.bottom-council-info h3 {
  font-size: 16px;
  font-weight: 800;
  color: #0f172a;
  margin: 0 0 2px;
}

.bottom-council-info span {
  font-size: 12px;
  color: #2563eb;
  font-weight: 700;
}

.bottom-council-desc {
  font-size: 13px;
  line-height: 1.6;
  color: #475569;
  margin: 0 0 16px;
}

/* Animated Equalizer Wave */
.equalizer-wave {
  display: inline-flex;
  align-items: flex-end;
  gap: 2px;
  height: 12px;
}

.eq-bar {
  width: 2.5px;
  background: #ffffff;
  border-radius: 1px;
  animation: eqBounce 1.2s infinite ease-in-out;
}

.eq-bar:nth-child(1) { height: 4px; animation-delay: 0s; }
.eq-bar:nth-child(2) { height: 10px; animation-delay: 0.2s; }
.eq-bar:nth-child(3) { height: 6px; animation-delay: 0.4s; }

@keyframes eqBounce {
  0%, 100% { transform: scaleY(0.4); }
  50% { transform: scaleY(1); }
}

/* ==========================================================================
   5. CELEBRATION CERTIFICATE MODAL
   ========================================================================== */
.cert-modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(7, 27, 66, 0.8);
  backdrop-filter: blur(8px);
  z-index: 100000;
  display: none;
  align-items: center;
  justify-content: center;
  padding: 20px;
}

.cert-modal-backdrop.open {
  display: flex;
  animation: fadeInModal 0.25s ease-out;
}

@keyframes fadeInModal {
  from { opacity: 0; }
  to { opacity: 1; }
}

.cert-modal-box {
  background: #ffffff;
  border-radius: 24px;
  max-width: 680px;
  width: 100%;
  padding: 32px;
  position: relative;
  box-shadow: 0 25px 60px rgba(0, 0, 0, 0.4);
  border: 2px solid #fbbf24;
}

.cert-modal-close {
  position: absolute;
  top: 18px;
  right: 18px;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: #f1f5f9;
  border: none;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  font-size: 18px;
  color: #64748b;
  transition: all 0.2s ease;
}

.cert-modal-close:hover {
  background: #e2e8f0;
  color: #0f172a;
}

.certificate-diploma-view {
  background: linear-gradient(135deg, #ffffff 0%, #f8fafc 100%);
  border: 6px double #1e40af;
  border-radius: 14px;
  padding: 28px;
  text-align: center;
  position: relative;
  margin-bottom: 20px;
}

.cert-diploma-logo {
  height: 36px;
  margin-bottom: 12px;
}

.cert-diploma-title {
  font-size: 20px;
  font-weight: 800;
  letter-spacing: 1px;
  text-transform: uppercase;
  color: #071b42;
  margin: 0 0 6px;
}

.cert-diploma-subtitle {
  font-size: 12px;
  color: #64748b;
  text-transform: uppercase;
  letter-spacing: 0.8px;
  margin: 0 0 14px;
}

.cert-recipient-name {
  font-size: 24px;
  font-weight: 800;
  color: #1e40af;
  border-bottom: 2px solid #fbbf24;
  display: inline-block;
  padding: 4px 24px;
  margin-bottom: 12px;
  min-width: 260px;
}

.cert-course-name {
  font-size: 14px;
  font-weight: 700;
  color: #0f172a;
  margin: 0 0 16px;
}

.cert-seal-strip {
  display: flex;
  align-items: center;
  justify-content: space-around;
  margin-top: 20px;
  padding-top: 14px;
  border-top: 1px dashed #cbd5e1;
}

.cert-signature-col {
  font-size: 11px;
  color: #64748b;
}

.cert-signature-line {
  font-weight: 700;
  color: #0f172a;
}

.btn-claim-cert {
  width: 100%;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 10px 16px;
  border-radius: 10px;
  font-size: 12.5px;
  font-weight: 700;
  background: linear-gradient(135deg, #fbbf24 0%, #f59e0b 100%);
  color: #071b42;
  border: none;
  cursor: pointer;
  transition: all 0.2s ease;
  box-shadow: 0 4px 12px rgba(251, 191, 36, 0.3);
}

.btn-claim-cert:hover:not(:disabled) {
  transform: translateY(-1.5px);
  box-shadow: 0 6px 18px rgba(251, 191, 36, 0.45);
}

.btn-claim-cert:disabled {
  opacity: 0.6;
  cursor: not-allowed;
  background: rgba(255, 255, 255, 0.2);
  color: rgba(255, 255, 255, 0.8);
  box-shadow: none;
}

/* ==========================================================================
   6. RESPONSIVE DESIGN & MOBILE OPTIMIZATIONS
   ========================================================================== */
@media (max-width: 1080px) {
  .course-stage-row {
    grid-template-columns: 1fr;
  }

  .transcript-sidebar-card {
    position: static;
    height: 480px;
    max-height: 520px;
  }
}

@media (max-width: 768px) {
  .course-hero-header-row {
    flex-direction: column;
    gap: 16px;
  }

  .course-hero-actions-col {
    align-items: flex-start;
    width: 100%;
  }

  .hero-action-btn-group {
    width: 100%;
  }

  .hero-btn {
    flex: 1;
    justify-content: center;
  }

  .player-sub-action-bar {
    flex-direction: column;
    align-items: stretch;
    gap: 12px;
  }

  .sub-bar-left,
  .sub-bar-right {
    justify-content: space-between;
    width: 100%;
  }

  .course-tab-content-area {
    padding: 18px 14px;
  }

  .episodes-grid-cards {
    grid-template-columns: 1fr;
  }
}