/* ================================
   TEACHING PAGE STYLES
   ================================ */

.teaching-container {
  max-width: 1400px;
  margin: 0 auto;
  padding: var(--spacing-md);
  background: linear-gradient(135deg, #f8fafc 0%, #e2e8f0 100%);
  min-height: 100vh;
}

.page-header {
  text-align: center;
  padding: var(--spacing-xl) 0;
  background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
  border-radius: var(--border-radius);
  margin-bottom: var(--spacing-xl);
  color: white;
  position: relative;
  overflow: hidden;
}

.page-header::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.1'%3E%3Ccircle cx='30' cy='30' r='2'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E") repeat;
  opacity: 0.1;
}

.header-content {
  position: relative;
  z-index: 2;
}

.page-header h1 {
  font-size: 3rem;
  margin-bottom: var(--spacing-sm);
  text-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.page-description {
  font-size: 1.2rem;
  margin-bottom: var(--spacing-lg);
  opacity: 0.9;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

.teaching-stats {
  display: flex;
  justify-content: center;
  gap: var(--spacing-lg);
  margin-top: var(--spacing-lg);
}

.stat-item {
  text-align: center;
  padding: var(--spacing-sm);
  background: rgba(255, 255, 255, 0.1);
  border-radius: var(--border-radius);
  backdrop-filter: blur(10px);
  border: 1px solid rgba(255, 255, 255, 0.2);
}

.stat-number {
  display: block;
  font-size: 2.5rem;
  font-weight: bold;
  line-height: 1;
}

.stat-label {
  font-size: 0.9rem;
  opacity: 0.8;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

/* Teaching Timeline */
.teaching-timeline {
  position: relative;
  padding: var(--spacing-lg) 0;
}

.teaching-timeline::before {
  content: '';
  position: absolute;
  left: 50px;
  top: 0;
  bottom: 0;
  width: 3px;
  background: linear-gradient(to bottom, var(--primary-color), var(--secondary-color), var(--accent-color));
  border-radius: 2px;
}

.year-section {
  margin-bottom: var(--spacing-xl);
  position: relative;
  animation: fadeInUp 0.6s ease-out;
}

.year-header {
  position: relative;
  margin-bottom: var(--spacing-lg);
  padding-left: 80px;
}

.year-indicator {
  position: absolute;
  left: 38px;
  top: 50%;
  transform: translateY(-50%);
  width: 28px;
  height: 28px;
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  border-radius: 50%;
  border: 4px solid white;
  box-shadow: 0 4px 12px rgba(0,0,0,0.15);
  z-index: 3;
}

.year-section h2 {
  font-size: 2.8rem;
  color: var(--primary-color);
  margin: 0;
  text-shadow: 0 2px 4px rgba(0,0,0,0.1);
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.semester-container {
  padding-left: 80px;
}

.semester-section {
  margin-bottom: var(--spacing-xl);
  position: relative;
}

.semester-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--spacing-lg);
  padding: var(--spacing-md);
  background: white;
  border-radius: var(--border-radius);
  box-shadow: var(--card-shadow);
  border-left: 5px solid var(--secondary-color);
}

.fall-semester .semester-header {
  border-left-color: #d97706;
  background: linear-gradient(135deg, #fef3c7 0%, #fde68a 100%);
}

.spring-semester .semester-header {
  border-left-color: #059669;
  background: linear-gradient(135deg, #d1fae5 0%, #a7f3d0 100%);
}

.summer-semester .semester-header {
  border-left-color: #dc2626;
  background: linear-gradient(135deg, #fed7d7 0%, #fbb6ce 100%);
}

.semester-header h3 {
  font-size: 1.8rem;
  margin: 0;
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  color: var(--text-color);
}

.semester-header i {
  font-size: 1.2rem;
}

.course-count {
  font-size: 0.9rem;
  color: var(--text-light);
  background: rgba(255, 255, 255, 0.7);
  padding: 0.25rem 0.75rem;
  border-radius: 20px;
  font-weight: 500;
}

/* Courses Grid */
.courses-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(380px, 1fr));
  gap: var(--spacing-lg);
}

.course-card {
  background: white;
  border-radius: var(--border-radius);
  overflow: hidden;
  box-shadow: var(--card-shadow);
  transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
  height: 100%;
  display: flex;
  flex-direction: column;
  border: 1px solid var(--border-color);
  position: relative;
}

.course-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(90deg, var(--primary-color), var(--secondary-color), var(--accent-color));
  opacity: 0;
  transition: opacity 0.3s ease;
}

.course-card:hover {
  transform: translateY(-12px) scale(1.02);
  box-shadow: 0 20px 40px rgba(0,0,0,0.15);
}

.course-card:hover::before {
  opacity: 1;
}

.course-image {
  height: 240px;
  position: relative;
  overflow: hidden;
  background: linear-gradient(135deg, var(--bg-light) 0%, #e9ecef 100%);
}

.course-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
  transition: transform 0.6s ease;
}

.course-card:hover .course-image img {
  transform: scale(1.1) rotate(1deg);
}

.image-overlay {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: linear-gradient(135deg, rgba(42, 88, 133, 0.8), rgba(74, 144, 226, 0.8));
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transition: opacity 0.3s ease;
}

.course-card:hover .image-overlay {
  opacity: 1;
}

.image-overlay i {
  font-size: 2rem;
  color: white;
}

.course-image-placeholder {
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
  color: white;
  font-size: 3.5rem;
  position: relative;
  overflow: hidden;
}

.placeholder-pattern {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: url("data:image/svg+xml,%3Csvg width='40' height='40' viewBox='0 0 40 40' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='%23ffffff' fill-opacity='0.1'%3E%3Cpath d='M20 20c0-8.837-7.163-16-16-16s-16 7.163-16 16 7.163 16 16 16 16-7.163 16-16zm16 0c0-8.837-7.163-16-16-16s-16 7.163-16 16 7.163 16 16 16 16-7.163 16-16z'/%3E%3C/g%3E%3C/svg%3E") repeat;
}

.course-badge {
  position: absolute;
  top: var(--spacing-sm);
  right: var(--spacing-sm);
  background: rgba(255, 255, 255, 0.9);
  color: var(--primary-color);
  padding: 0.25rem 0.75rem;
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  backdrop-filter: blur(10px);
}

.course-content {
  padding: var(--spacing-lg);
  flex-grow: 1;
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.course-header {
  margin-bottom: var(--spacing-sm);
}

.course-content h4 {
  margin: 0 0 var(--spacing-xs) 0;
  font-size: 1.4rem;
  line-height: 1.3;
}

.course-content h4 a {
  color: var(--text-color);
  text-decoration: none;
  transition: color 0.3s ease;
}

.course-content h4 a:hover {
  color: var(--primary-color);
}

.course-code {
  font-weight: 700;
  color: white;
  font-size: 0.9rem;
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  padding: 0.4rem 0.8rem;
  border-radius: 20px;
  display: inline-block;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.course-level {
  display: inline-block;
  background-color: rgba(89, 131, 146, 0.1);
  color: var(--secondary-color);
  padding: 0.2rem 0.5rem;
  border-radius: var(--border-radius-sm);
  font-size: 0.8rem;
  margin-bottom: var(--spacing-xs);
}

.course-meta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-sm);
}

.course-meta .meta-item {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  font-size: 0.85rem;
  color: var(--text-light);
  background: var(--bg-light);
  padding: 0.25rem 0.5rem;
  border-radius: 15px;
}

.course-meta .meta-item i {
  font-size: 0.8rem;
  color: var(--primary-color);
}

.course-summary {
  flex-grow: 1;
  color: var(--text-light);
  font-size: 0.95rem;
  line-height: 1.6;
  margin-bottom: var(--spacing-md);
}

.course-footer {
  margin-top: auto;
}

.btn-course-details {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
  padding: 0.75rem 1.5rem;
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  color: white;
  text-decoration: none;
  border-radius: 25px;
  font-weight: 600;
  transition: all 0.3s ease;
  border: none;
  cursor: pointer;
}

.btn-course-details:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(42, 88, 133, 0.3);
  background: linear-gradient(135deg, var(--secondary-color), var(--accent-color));
}

.btn-course-details i {
  transition: transform 0.3s ease;
}

.btn-course-details:hover i {
  transform: translateX(4px);
}

/* ================================
   COURSE SINGLE PAGE
   ================================ */

.course-single {
  max-width: 1000px;
  margin: 0 auto;
  padding: var(--spacing-lg);
  background-color: white;
  border-radius: var(--border-radius);
  box-shadow: var(--card-shadow);
  line-height: 1.6;
}

.course-header {
  margin-bottom: var(--spacing-xl);
  padding-bottom: var(--spacing-lg);
  border-bottom: 2px solid var(--border-color);
}

.course-title-section {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--spacing-lg);
  flex-wrap: wrap;
  gap: var(--spacing-sm);
}

.course-title-section h1 {
  font-size: 2.5rem;
  color: var(--primary-color);
  margin: 0;
  flex: 1;
  min-width: 300px;
}

.course-code-badge {
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  color: white;
  padding: 0.5rem 1rem;
  border-radius: 25px;
  font-weight: 600;
  font-size: 1rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.course-meta-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--spacing-md);
  margin-top: var(--spacing-lg);
}

.course-meta-grid .meta-item {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-sm);
  background-color: var(--bg-light);
  border-radius: var(--border-radius);
  border: 1px solid var(--border-color);
}

.course-meta-grid .meta-item i {
  color: var(--primary-color);
  font-size: 1.1rem;
  width: 20px;
  text-align: center;
}

.meta-content {
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
}

.meta-label {
  font-size: 0.8rem;
  color: var(--text-light);
  text-transform: uppercase;
  font-weight: 600;
  letter-spacing: 0.5px;
}

.meta-value {
  font-size: 1rem;
  color: var(--text-color);
  font-weight: 500;
}

.featured-image {
  position: relative;
  margin-bottom: var(--spacing-xl);
  border-radius: var(--border-radius);
  overflow: hidden;
  box-shadow: var(--card-shadow);
}

.featured-image img {
  width: 100%;
  height: 300px;
  object-fit: cover;
  object-position: center;
  transition: transform 0.3s ease;
}

.featured-image:hover img {
  transform: scale(1.05);
}

.course-summary-section {
  margin-bottom: var(--spacing-xl);
  padding: var(--spacing-lg);
  background: linear-gradient(135deg, var(--bg-light), #f1f5f9);
  border-radius: var(--border-radius);
  border-left: 4px solid var(--primary-color);
}

.course-summary-section h2 {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-md);
  color: var(--primary-color);
}

.summary-content p {
  font-size: 1.1rem;
  line-height: 1.7;
  color: var(--text-color);
  margin: 0;
}

.quick-info-section {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--spacing-lg);
  margin-bottom: var(--spacing-xl);
}

.info-card {
  background: white;
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  padding: var(--spacing-lg);
  box-shadow: var(--card-shadow);
  transition: var(--transition);
}

.info-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--hover-shadow);
}

.info-card h3 {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-md);
  color: var(--primary-color);
  font-size: 1.2rem;
}

.prerequisites-list,
.objectives-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.prerequisites-list li,
.objectives-list li {
  padding: 0.5rem 0;
  border-bottom: 1px solid var(--border-color);
  position: relative;
  padding-left: 1.5rem;
}

.prerequisites-list li:before,
.objectives-list li:before {
  content: "✓";
  color: var(--success-color);
  font-weight: bold;
  position: absolute;
  left: 0;
}

.prerequisites-list li:last-child,
.objectives-list li:last-child {
  border-bottom: none;
}

.textbooks-list {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.textbook-item {
  padding: var(--spacing-sm);
  background-color: var(--bg-light);
  border-radius: var(--border-radius-sm);
  position: relative;
}

.authors {
  color: var(--text-light);
  font-size: 0.9rem;
}

.required-badge,
.optional-badge {
  position: absolute;
  top: var(--spacing-xs);
  right: var(--spacing-xs);
  padding: 0.2rem 0.5rem;
  border-radius: 12px;
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
}

.required-badge {
  background-color: var(--success-color);
  color: white;
}

.optional-badge {
  background-color: var(--text-light);
  color: white;
}

.grading-breakdown {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.grade-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.5rem;
  background-color: var(--bg-light);
  border-radius: var(--border-radius-sm);
}

.grade-category {
  font-weight: 500;
}

.grade-percentage {
  font-weight: 700;
  color: var(--primary-color);
}

.course-actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-md);
  align-items: center;
  padding: var(--spacing-lg);
  background-color: var(--bg-light);
  border-radius: var(--border-radius);
  margin-bottom: var(--spacing-xl);
}

.office-hours-info {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  color: var(--text-color);
  font-size: 0.9rem;
}

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

.course-tags h3 {
  margin-bottom: var(--spacing-md);
  color: var(--primary-color);
}

.tags-container {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
}

.course-content {
  margin: var(--spacing-xl) 0;
  font-size: 1.05rem;
  line-height: 1.7;
}

.course-content h2 {
  color: var(--primary-color);
  margin-top: var(--spacing-xl);
  margin-bottom: var(--spacing-md);
  font-size: 1.8rem;
}

.course-content h3 {
  color: var(--secondary-color);
  margin-top: var(--spacing-lg);
  margin-bottom: var(--spacing-sm);
}

.tools-section {
  margin-bottom: var(--spacing-xl);
  padding: var(--spacing-lg);
  background-color: var(--bg-light);
  border-radius: var(--border-radius);
}

.tools-section h2 {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-md);
  color: var(--primary-color);
}

.tools-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minWidth(200px, 1fr));
  gap: var(--spacing-sm);
}

.tool-item {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  padding: 0.5rem;
  background: white;
  border-radius: var(--border-radius-sm);
  font-weight: 500;
}

.tool-item i {
  color: var(--primary-color);
}

.course-navigation {
  margin-top: var(--spacing-xl);
  padding-top: var(--spacing-lg);
  border-top: 2px solid var(--border-color);
}

.back-to-teaching {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
  color: var(--primary-color);
  text-decoration: none;
  font-weight: 500;
  margin-bottom: var(--spacing-md);
  transition: color 0.2s ease;
}

.back-to-teaching:hover {
  color: var(--secondary-color);
}

.nav-links {
  display: flex;
  justify-content: space-between;
  gap: var(--spacing-lg);
}

.nav-link {
  flex: 1;
  padding: var(--spacing-md);
  background: white;
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  text-decoration: none;
  color: var(--text-color);
  transition: var(--transition);
  max-width: 45%;
}

.nav-link:hover {
  transform: translateY(-3px);
  box-shadow: var(--hover-shadow);
  border-color: var(--primary-color);
}

.next-link {
  text-align: right;
}

.nav-direction {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  font-size: 0.8rem;
  color: var(--text-light);
  text-transform: uppercase;
  font-weight: 600;
  margin-bottom: 0.25rem;
}

.next-link .nav-direction {
  justify-content: flex-end;
}

.nav-title {
  font-weight: 500;
  color: var(--primary-color);
}

/* ================================
   RESPONSIVE DESIGN
   ================================ */

@media (max-width: 1200px) {
  .courses-grid {
    grid-template-columns: repeat(auto-fill, minWidth(340px, 1fr));
    gap: var(--spacing-md);
  }
}

@media (max-width: 768px) {
  .teaching-timeline::before {
    left: 20px;
  }
  
  .year-header,
  .semester-container {
    padding-left: 50px;
  }
  
  .year-indicator {
    left: 8px;
    width: 24px;
    height: 24px;
  }
  
  .courses-grid {
    grid-template-columns: 1fr;
  }
  
  .course-image {
    height: 200px;
  }
  
  .page-header h1 {
    font-size: 2.2rem;
  }
  
  .year-section h2 {
    font-size: 2rem;
  }
  
  .semester-header {
    flex-direction: column;
    gap: var(--spacing-xs);
    align-items: flex-start;
  }
  
  .teaching-stats {
    flex-direction: column;
    gap: var(--spacing-sm);
  }
  
  .course-single {
    padding: var(--spacing-md);
    margin: var(--spacing-sm);
  }
  
  .course-title-section {
    flex-direction: column;
    align-items: flex-start;
  }
  
  .course-title-section h1 {
    font-size: 2rem;
    min-width: auto;
  }
  
  .course-meta-grid {
    grid-template-columns: 1fr;
  }
  
  .quick-info-section {
    grid-template-columns: 1fr;
  }
  
  .course-actions {
    flex-direction: column;
    align-items: flex-start;
  }
  
  .nav-links {
    flex-direction: column;
  }
  
  .nav-link {
    max-width: 100%;
  }
  
  .tools-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 576px) {
  .teaching-container {
    padding: var(--spacing-sm);
  }
  
  .course-image {
    height: 180px;
  }
  
  .course-content {
    padding: var(--spacing-md);
  }
  
  .course-content h4 {
    font-size: 1.2rem;
  }
  
  .course-image-placeholder {
    font-size: 2.5rem;
  }
  
  .page-header {
    padding: var(--spacing-lg) var(--spacing-sm);
  }
  
  .page-header h1 {
    font-size: 1.8rem;
  }
  
  .featured-image img {
    height: 200px;
  }
  
  .course-title-section h1 {
    font-size: 1.7rem;
  }
  
  .course-summary-section,
  .info-card {
    padding: var(--spacing-md);
  }
}