/* ==========================================================================
   COURSE DETAIL PAGE STYLES
   ========================================================================== */

/* COURSE HERO SECTION
   ========================================================================== */

.course-hero {
  position: relative;
  min-height: 80vh;
  display: flex;
  align-items: center;
  overflow: hidden;
  margin-top: 70px;
}

.course-hero-bg {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 1;
}

.course-hero-image {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.course-hero-overlay {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(
    135deg,
    rgba(18, 18, 18, 0.8) 0%,
    rgba(26, 26, 26, 0.6) 50%,
    rgba(99, 102, 241, 0.3) 100%
  );
  backdrop-filter: blur(2px);
  -webkit-backdrop-filter: blur(2px);
}

.course-hero-content {
  position: relative;
  z-index: 2;
  max-width: 800px;
  color: var(--color-text-primary);
}

.course-breadcrumb {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-lg);
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
}

.course-breadcrumb a {
  color: var(--color-text-secondary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.course-breadcrumb a:hover {
  color: #ffffff;
  text-shadow: 0 1px 2px rgba(0, 0, 0, 0.3);
}

.course-hero-badge {
  display: flex;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-lg);
}

.badge-featured,
.badge-level {
  padding: var(--spacing-xs) var(--spacing-md);
  border-radius: var(--border-radius-full);
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-semibold);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.badge-featured {
  background: linear-gradient(135deg, var(--color-secondary) 0%, #d97706 100%);
  color: var(--color-text-primary);
}

.badge-level {
  background: rgba(255, 255, 255, 0.2);
  color: var(--color-text-primary);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border: 1px solid rgba(255, 255, 255, 0.3);
}

.course-hero-title {
  font-size: var(--font-size-5xl);
  font-weight: var(--font-weight-black);
  line-height: var(--line-height-tight);
  margin-bottom: var(--spacing-lg);
  background: linear-gradient(135deg, #ffffff 0%, #e5e5e5 50%, var(--color-primary-light) 100%);
  background-clip: text;
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.course-hero-subtitle {
  font-size: var(--font-size-xl);
  line-height: var(--line-height-relaxed);
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-2xl);
}

.course-hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-lg);
  margin-bottom: var(--spacing-2xl);
}

.meta-item {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  color: var(--color-text-secondary);
  font-size: var(--font-size-sm);
  background: rgba(255, 255, 255, 0.1);
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: var(--border-radius-lg);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}

.meta-icon {
  font-size: var(--font-size-base);
}

.course-hero-actions {
  display: flex;
  gap: var(--spacing-md);
  flex-wrap: wrap;
}

.btn-hero-primary {
  padding: var(--spacing-md) var(--spacing-2xl);
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
  color: var(--color-text-primary);
  border: none;
  border-radius: var(--border-radius-xl);
  font-weight: var(--font-weight-semibold);
  font-size: var(--font-size-lg);
  cursor: pointer;
  transition: all var(--transition-normal);
  box-shadow: 0 8px 25px rgba(99, 102, 241, 0.3);
}

.btn-hero-primary:hover {
  box-shadow: 0 12px 35px rgba(99, 102, 241, 0.4);
}

.btn-hero-secondary {
  padding: var(--spacing-md) var(--spacing-2xl);
  background: transparent;
  color: var(--color-text-primary);
  border: 2px solid rgba(255, 255, 255, 0.3);
  border-radius: var(--border-radius-xl);
  font-weight: var(--font-weight-semibold);
  font-size: var(--font-size-lg);
  cursor: pointer;
  transition: all var(--transition-normal);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}

.btn-hero-secondary:hover {
  background: rgba(255, 255, 255, 0.15);
  border-color: rgba(255, 255, 255, 0.8);
  color: #ffffff;
  text-shadow: 0 1px 2px rgba(0, 0, 0, 0.3);
}

/* COURSE MAIN LAYOUT
   ========================================================================== */

.course-main {
  padding: var(--spacing-5xl) 0;
  background: var(--color-bg-primary);
}

.course-layout {
  display: grid;
  grid-template-columns: 1fr 400px;
  gap: var(--spacing-4xl);
  align-items: start;
}

.course-content {
  min-width: 0;
}

.course-section {
  margin-bottom: var(--spacing-4xl);
}

.section-title {
  font-size: var(--font-size-3xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-text-primary);
  margin-bottom: var(--spacing-2xl);
  position: relative;
}

.section-title::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: -12px;
  width: 60px;
  height: 3px;
  background: linear-gradient(90deg, var(--color-primary) 0%, var(--color-primary-light) 100%);
  border-radius: var(--border-radius-full);
}

/* COURSE OVERVIEW SECTION
   ========================================================================== */

.course-overview {
  display: grid;
  grid-template-columns: 2fr 1fr;
  gap: var(--spacing-3xl);
}

.overview-description {
  color: var(--color-text-secondary);
  line-height: var(--line-height-relaxed);
}

.overview-description p {
  margin-bottom: var(--spacing-lg);
  font-size: var(--font-size-lg);
}

.overview-description h3 {
  color: var(--color-text-primary);
  margin: var(--spacing-2xl) 0 var(--spacing-lg) 0;
  font-size: var(--font-size-xl);
}

.learning-outcomes {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

.outcome-item {
  display: flex;
  align-items: flex-start;
  gap: var(--spacing-md);
  padding: var(--spacing-md);
  background: var(--color-bg-card);
  border-radius: var(--border-radius-lg);
  border: 1px solid rgba(255, 255, 255, 0.1);
  transition: all var(--transition-fast);
}

.outcome-item:hover {
  background: var(--color-bg-hover);
  border-color: rgba(99, 102, 241, 0.3);
}

.outcome-icon {
  color: var(--color-success);
  font-size: var(--font-size-lg);
  margin-top: 2px;
}

.overview-highlights {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

.highlight-card {
  background: var(--color-bg-card);
  padding: var(--spacing-xl);
  border-radius: var(--border-radius-xl);
  border: 1px solid rgba(255, 255, 255, 0.1);
  text-align: center;
  transition: all var(--transition-normal);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}

.highlight-card:hover {
  border-color: rgba(99, 102, 241, 0.3);
  box-shadow: 0 12px 30px rgba(0, 0, 0, 0.3);
}

.highlight-card h4 {
  font-size: var(--font-size-lg);
  color: var(--color-text-primary);
  margin-bottom: var(--spacing-sm);
}

.highlight-card p {
  color: var(--color-text-muted);
  font-size: var(--font-size-sm);
  margin: 0;
}

/* SYLLABUS ACCORDION - CSS ONLY
   ========================================================================== */

.syllabus-accordion {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

.accordion-item {
  background: var(--color-bg-card);
  border-radius: var(--border-radius-xl);
  border: 1px solid rgba(255, 255, 255, 0.1);
  overflow: hidden;
  transition: all var(--transition-normal);
}

.accordion-item:hover {
  border-color: rgba(99, 102, 241, 0.3);
}

.accordion-checkbox {
  display: none;
}

.accordion-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--spacing-xl);
  cursor: pointer;
  transition: all var(--transition-fast);
  background: transparent;
}

.accordion-header:hover {
  background: rgba(99, 102, 241, 0.05);
}

.accordion-title h3 {
  font-size: var(--font-size-xl);
  color: var(--color-text-primary);
  margin: 0;
  margin-bottom: var(--spacing-xs);
}

.accordion-meta {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
}

.accordion-arrow {
  font-size: var(--font-size-lg);
  color: var(--color-primary-light);
  transition: transform var(--transition-fast);
}

.accordion-checkbox:checked + .accordion-header .accordion-arrow {
  transform: rotate(180deg);
}

.accordion-content {
  max-height: 0;
  overflow: hidden;
  transition: max-height var(--transition-slow);
}

.accordion-checkbox:checked ~ .accordion-content {
  max-height: 1000px;
}

/* Add visual feedback for checked state */
.accordion-checkbox:checked + .accordion-header {
  background: rgba(99, 102, 241, 0.08);
}

.accordion-checkbox:checked + .accordion-header .accordion-title h3 {
  color: var(--color-primary-light);
}

.lesson-list {
  padding: 0 var(--spacing-xl) var(--spacing-xl);
  border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.lesson-item {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  padding: var(--spacing-md) 0;
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
  transition: all var(--transition-fast);
}

.lesson-item:last-child {
  border-bottom: none;
}

.lesson-item:hover {
  background: rgba(99, 102, 241, 0.05);
  margin: 0 calc(-1 * var(--spacing-md));
  padding-left: var(--spacing-md);
  padding-right: var(--spacing-md);
  border-radius: var(--border-radius-md);
}

.lesson-icon {
  font-size: var(--font-size-lg);
}

.lesson-info {
  flex: 1;
}

.lesson-info h4 {
  font-size: var(--font-size-base);
  color: var(--color-text-primary);
  margin: 0;
  margin-bottom: 2px;
  transition: color var(--transition-fast);
}

.lesson-item:hover .lesson-info h4 {
  color: var(--color-primary-light);
}

.lesson-duration {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
}

.lesson-type {
  padding: var(--spacing-xs) var(--spacing-sm);
  background: rgba(99, 102, 241, 0.2);
  color: var(--color-primary-light);
  border-radius: var(--border-radius-md);
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-semibold);
  text-transform: uppercase;
}

.lesson-item:hover .lesson-type {
  background: rgba(99, 102, 241, 0.3);
}

/* INSTRUCTOR BIO SECTION
   ========================================================================== */

.instructor-bio {
  background: var(--color-bg-card);
  border-radius: var(--border-radius-2xl);
  padding: var(--spacing-2xl);
  border: 1px solid rgba(255, 255, 255, 0.1);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}

.instructor-card {
  display: grid;
  grid-template-columns: 200px 1fr;
  gap: var(--spacing-2xl);
  align-items: start;
}

.instructor-avatar {
  position: relative;
}

.instructor-avatar img {
  width: 200px;
  height: 200px;
  border-radius: var(--border-radius-2xl);
  object-fit: cover;
  border: 3px solid rgba(99, 102, 241, 0.3);
  transition: all var(--transition-normal);
}

.instructor-avatar:hover img {
  border-color: var(--color-primary);
  box-shadow: 0 8px 25px rgba(99, 102, 241, 0.3);
}

.instructor-info h3 {
  font-size: var(--font-size-2xl);
  color: var(--color-text-primary);
  margin: 0;
  margin-bottom: var(--spacing-xs);
}

.instructor-title {
  font-size: var(--font-size-lg);
  color: var(--color-primary-light);
  margin-bottom: var(--spacing-lg);
  font-weight: var(--font-weight-medium);
}

.instructor-stats {
  display: flex;
  gap: var(--spacing-xl);
  margin-bottom: var(--spacing-lg);
}

.stat-item {
  text-align: center;
}

.stat-number {
  display: block;
  font-size: var(--font-size-2xl);
  font-weight: var(--font-weight-black);
  color: var(--color-primary-light);
}

.stat-label {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.instructor-description {
  color: var(--color-text-secondary);
  line-height: var(--line-height-relaxed);
  margin-bottom: var(--spacing-lg);
}

.instructor-description p {
  margin-bottom: var(--spacing-md);
}

.instructor-credentials {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
}

.credential {
  padding: var(--spacing-xs) var(--spacing-md);
  background: rgba(99, 102, 241, 0.1);
  color: var(--color-primary-light);
  border-radius: var(--border-radius-full);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
}

/* TESTIMONIALS SECTION
   ========================================================================== */

.testimonials {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
  gap: var(--spacing-xl);
}

.testimonial-card {
  background: var(--color-bg-card);
  border-radius: var(--border-radius-xl);
  padding: var(--spacing-xl);
  border: 1px solid rgba(255, 255, 255, 0.1);
  transition: all var(--transition-normal);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}

.testimonial-card:hover {
  border-color: rgba(99, 102, 241, 0.3);
  box-shadow: 0 12px 30px rgba(0, 0, 0, 0.3);
}

.testimonial-header {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-lg);
}

.student-avatar img {
  width: 60px;
  height: 60px;
  border-radius: 50%;
  object-fit: cover;
  border: 2px solid rgba(99, 102, 241, 0.3);
}

.student-info h4 {
  font-size: var(--font-size-lg);
  color: var(--color-text-primary);
  margin: 0;
  margin-bottom: 2px;
}

.student-info p {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  margin: 0;
  margin-bottom: var(--spacing-xs);
}

.rating {
  color: var(--color-secondary);
  font-size: var(--font-size-sm);
}

.testimonial-content {
  font-style: italic;
  color: var(--color-text-secondary);
  line-height: var(--line-height-relaxed);
  margin-bottom: var(--spacing-md);
  border-left: 3px solid var(--color-primary);
  padding-left: var(--spacing-lg);
}

.testimonial-date {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  text-align: right;
}

/* STICKY SIDEBAR
   ========================================================================== */

.course-sidebar {
  position: relative;
}

.sidebar-sticky {
  position: sticky;
  top: calc(70px + var(--spacing-lg));
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xl);
}

/* Course Preview */
.course-preview {
  background: var(--color-bg-card);
  border-radius: var(--border-radius-xl);
  overflow: hidden;
  border: 1px solid rgba(255, 255, 255, 0.1);
}

.preview-video {
  position: relative;
  height: 225px;
  overflow: hidden;
}

.preview-video img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.play-button {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  background: rgba(0, 0, 0, 0.8);
  color: var(--color-text-primary);
  border: none;
  border-radius: var(--border-radius-lg);
  padding: var(--spacing-md) var(--spacing-lg);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-semibold);
  cursor: pointer;
  transition: all var(--transition-fast);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.play-button:hover {
  background: rgba(0, 0, 0, 0.9);
}

/* Pricing Card */
.pricing-card {
  background: var(--color-bg-card);
  border-radius: var(--border-radius-xl);
  padding: var(--spacing-xl);
  border: 1px solid rgba(255, 255, 255, 0.1);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}

.price-header {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-lg);
  position: relative;
}

.current-price {
  font-size: var(--font-size-4xl);
  font-weight: var(--font-weight-black);
  color: var(--color-primary-light);
}

.original-price {
  font-size: var(--font-size-xl);
  color: var(--color-text-muted);
  text-decoration: line-through;
}

.discount-badge {
  position: absolute;
  top: -8px;
  right: 0;
  background: linear-gradient(135deg, var(--color-danger) 0%, #dc2626 100%);
  color: var(--color-text-primary);
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: var(--border-radius-md);
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-bold);
  text-transform: uppercase;
}

.price-timer {
  background: rgba(239, 68, 68, 0.1);
  border: 1px solid rgba(239, 68, 68, 0.3);
  border-radius: var(--border-radius-lg);
  padding: var(--spacing-md);
  margin-bottom: var(--spacing-lg);
  text-align: center;
}

.timer-text {
  display: block;
  font-size: var(--font-size-sm);
  color: var(--color-danger);
  margin-bottom: var(--spacing-sm);
  font-weight: var(--font-weight-semibold);
}

.countdown {
  display: flex;
  justify-content: center;
  gap: var(--spacing-sm);
  align-items: center;
}

.time-unit {
  display: flex;
  flex-direction: column;
  align-items: center;
}

.time-number {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-black);
  color: var(--color-danger);
}

.time-label {
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
  text-transform: uppercase;
}

.time-separator {
  font-size: var(--font-size-xl);
  color: var(--color-danger);
  font-weight: var(--font-weight-bold);
}

.enroll-button {
  width: 100%;
  padding: var(--spacing-md) var(--spacing-lg);
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
  color: var(--color-text-primary);
  border: none;
  border-radius: var(--border-radius-lg);
  font-weight: var(--font-weight-semibold);
  font-size: var(--font-size-lg);
  cursor: pointer;
  transition: all var(--transition-fast);
  margin-bottom: var(--spacing-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  box-shadow: 0 8px 25px rgba(99, 102, 241, 0.3);
}

.enroll-button:hover {
  box-shadow: 0 12px 35px rgba(99, 102, 241, 0.4);
  background: linear-gradient(135deg, var(--color-primary-light), var(--color-primary));
  color: #ffffff;
  text-shadow: 0 1px 2px rgba(0, 0, 0, 0.2);
}

.guarantee {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  color: var(--color-text-muted);
  font-size: var(--font-size-sm);
  text-align: center;
}

.guarantee-icon {
  font-size: var(--font-size-base);
}

/* Course Features Sidebar */
.course-features-sidebar {
  background: var(--color-bg-card);
  border-radius: var(--border-radius-xl);
  padding: var(--spacing-xl);
  border: 1px solid rgba(255, 255, 255, 0.1);
}

.course-features-sidebar h3 {
  font-size: var(--font-size-lg);
  color: var(--color-text-primary);
  margin-bottom: var(--spacing-lg);
}

.features-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.feature-item {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  padding: var(--spacing-sm) 0;
  color: var(--color-text-secondary);
  font-size: var(--font-size-sm);
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
  transition: all var(--transition-fast);
}

.feature-item:last-child {
  border-bottom: none;
}

.feature-item:hover {
  color: var(--color-text-primary);
  transform: translateX(4px);
}

.feature-icon {
  font-size: var(--font-size-base);
}

/* Share Course */
.share-course {
  background: var(--color-bg-card);
  border-radius: var(--border-radius-xl);
  padding: var(--spacing-xl);
  border: 1px solid rgba(255, 255, 255, 0.1);
}

.share-course h3 {
  font-size: var(--font-size-lg);
  color: var(--color-text-primary);
  margin-bottom: var(--spacing-lg);
}

.share-buttons {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing-sm);
}

.share-btn {
  padding: var(--spacing-sm) var(--spacing-md);
  border: 1px solid rgba(255, 255, 255, 0.2);
  border-radius: var(--border-radius-md);
  background: transparent;
  color: var(--color-text-secondary);
  font-size: var(--font-size-sm);
  cursor: pointer;
  transition: all var(--transition-fast);
  text-align: center;
}

.share-btn:hover {
  background: rgba(255, 255, 255, 0.15);
  border-color: rgba(255, 255, 255, 0.6);
  color: #ffffff;
  text-shadow: 0 1px 2px rgba(0, 0, 0, 0.3);
}

.share-btn.twitter:hover {
  background: rgba(29, 161, 242, 0.2);
  border-color: #1da1f2;
}

.share-btn.facebook:hover {
  background: rgba(24, 119, 242, 0.2);
  border-color: #1877f2;
}

.share-btn.linkedin:hover {
  background: rgba(10, 102, 194, 0.2);
  border-color: #0a66c2;
}

.share-btn.copy:hover {
  background: rgba(99, 102, 241, 0.2);
  border-color: var(--color-primary);
}

/* COUNTDOWN TIMER STYLES
   ========================================================================== */

.countdown-hours,
.countdown-minutes,
.countdown-seconds {
  color: var(--color-danger);
}

/* CSS-ONLY BACK TO TOP BUTTON
   ========================================================================== */

.back-to-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  width: 50px;
  height: 50px;
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
  color: var(--color-text-primary);
  border: none;
  border-radius: 50%;
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-bold);
  cursor: pointer;
  z-index: 1000;
  transition: all var(--transition-normal);
  box-shadow: 0 4px 15px rgba(99, 102, 241, 0.3);
  opacity: 1;
}

.back-to-top:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 25px rgba(99, 102, 241, 0.4);
}

/* STATIC BADGE STYLES
   ========================================================================== */

/* STATIC BUTTON STYLES
   ========================================================================== */

.enroll-button {
  box-shadow: 0 8px 25px rgba(99, 102, 241, 0.3);
}

/* CSS-ONLY TOOLTIP SYSTEM
   ========================================================================== */

[data-tooltip] {
  position: relative;
  cursor: help;
}

[data-tooltip]:before {
  content: attr(data-tooltip);
  position: absolute;
  bottom: 100%;
  left: 50%;
  transform: translateX(-50%);
  background: rgba(0, 0, 0, 0.9);
  color: var(--color-text-primary);
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: var(--border-radius-md);
  font-size: var(--font-size-sm);
  white-space: nowrap;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-fast);
  z-index: 1000;
  margin-bottom: 8px;
}

[data-tooltip]:after {
  content: '';
  position: absolute;
  bottom: 100%;
  left: 50%;
  transform: translateX(-50%);
  border: 5px solid transparent;
  border-top-color: rgba(0, 0, 0, 0.9);
  opacity: 0;
  transition: opacity var(--transition-fast);
  margin-bottom: 3px;
}

[data-tooltip]:hover:before,
[data-tooltip]:hover:after {
  opacity: 1;
}

/* Large screens */
@media (min-width: 1200px) {
  .course-layout {
    grid-template-columns: 1fr 450px;
  }
  
  .course-overview {
    grid-template-columns: 2.5fr 1fr;
  }
}

/* Medium screens and tablets */
@media (max-width: 1024px) {
  .course-hero-title {
    font-size: var(--font-size-4xl);
  }
  
  .course-layout {
    grid-template-columns: 1fr;
    gap: var(--spacing-2xl);
  }
  
  .sidebar-sticky {
    position: static;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-lg);
  }
  
  .course-overview {
    grid-template-columns: 1fr;
    gap: var(--spacing-xl);
  }
  
  .overview-highlights {
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    display: grid;
  }
  
  .instructor-card {
    grid-template-columns: 150px 1fr;
    gap: var(--spacing-xl);
  }
  
  .instructor-avatar img {
    width: 150px;
    height: 150px;
  }
  
  .instructor-stats {
    gap: var(--spacing-md);
  }
}

/* Small tablets and large phones */
@media (max-width: 768px) {
  .course-hero {
    min-height: 60vh;
  }
  
  .course-hero-title {
    font-size: var(--font-size-3xl);
  }
  
  .course-hero-subtitle {
    font-size: var(--font-size-lg);
  }
  
  .course-hero-meta {
    gap: var(--spacing-md);
  }
  
  .course-hero-actions {
    flex-direction: column;
  }
  
  .btn-hero-primary,
  .btn-hero-secondary {
    width: 100%;
    text-align: center;
    justify-content: center;
  }
  
  .course-main {
    padding: var(--spacing-3xl) 0;
  }
  
  .section-title {
    font-size: var(--font-size-2xl);
  }
  
  .testimonials {
    grid-template-columns: 1fr;
  }
  
  .instructor-card {
    grid-template-columns: 1fr;
    text-align: center;
    gap: var(--spacing-lg);
  }
  
  .instructor-stats {
    justify-content: center;
  }
  
  .sidebar-sticky {
    grid-template-columns: 1fr;
  }
}

/* Mobile phones */
@media (max-width: 576px) {
  .course-hero {
    min-height: 50vh;
  }
  
  .course-hero-content {
    text-align: center;
  }
  
  .course-hero-title {
    font-size: var(--font-size-2xl);
  }
  
  .course-hero-meta {
    justify-content: center;
    flex-direction: column;
    gap: var(--spacing-sm);
  }
  
  .course-main {
    padding: var(--spacing-2xl) 0;
  }
  
  .overview-description p {
    font-size: var(--font-size-base);
  }
  
  .outcome-item {
    flex-direction: column;
    text-align: center;
    gap: var(--spacing-sm);
  }
  
  .accordion-header {
    padding: var(--spacing-lg);
  }
  
  .accordion-title h3 {
    font-size: var(--font-size-lg);
  }
  
  .lesson-list {
    padding: 0 var(--spacing-lg) var(--spacing-lg);
  }
  
  .instructor-avatar img {
    width: 120px;
    height: 120px;
  }
  
  .instructor-stats {
    flex-direction: column;
    gap: var(--spacing-sm);
  }
  
  .pricing-card,
  .course-features-sidebar,
  .share-course {
    padding: var(--spacing-lg);
  }
  
  .share-buttons {
    grid-template-columns: 1fr;
  }
  
  .countdown {
    gap: 2px;
  }
  
  .time-number {
    font-size: var(--font-size-lg);
  }
}

/* Accessibility improvements */
@media (prefers-reduced-motion: reduce) {
  .highlight-card:hover,
  .testimonial-card:hover,
  .enroll-button:hover,
  .btn-hero-primary:hover,
  .btn-hero-secondary:hover {
    transform: none;
  }
  
  .outcome-item:hover,
  .feature-item:hover {
    transform: none;
  }
  
  .instructor-avatar:hover img {
    transform: none;
  }
}

/* High contrast mode support */
@media (prefers-contrast: high) {
  .course-hero-overlay {
    background: rgba(0, 0, 0, 0.8);
  }
  
  .course-hero-title,
  .section-title {
    background: none;
    -webkit-text-fill-color: var(--color-text-primary);
    color: var(--color-text-primary);
  }
  
  .accordion-item,
  .testimonial-card,
  .pricing-card,
  .course-features-sidebar {
    border: 2px solid var(--color-text-primary);
  }
  
  .btn-hero-primary,
  .btn-hero-secondary,
  .enroll-button {
    border: 2px solid var(--color-primary);
  }
}