:root {
  --primary: #1A237E;
  --primary-light: #3949AB;
  --accent: #FF6F00;
  --bg: #F5F5F5;
  --text: #212121;
  --text-muted: #757575;
  --success: #2E7D32;
  --error: #C62828;
  --border: #E0E0E0;
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
}

.hero-section {
  background: linear-gradient(135deg, var(--primary), var(--primary-light));
  color: white;
  padding: 60px 0;
}

.course-card {
  border: none;
  border-radius: 12px;
  transition: transform 0.2s, box-shadow 0.2s;
  overflow: hidden;
}

.course-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 24px rgba(0,0,0,0.12);
}

.course-card .card-img-top {
  height: 180px;
  object-fit: cover;
  background: var(--primary);
}

.level-badge {
  font-size: 11px;
  padding: 2px 8px;
  border-radius: 4px;
  background: rgba(26,35,126,0.1);
  color: var(--primary);
}

.auth-form {
  max-width: 440px;
  margin: 0 auto;
}

.auth-form .card {
  border: none;
  border-radius: 16px;
}

.lesson-list .list-group-item {
  border-left: none;
  border-right: none;
  padding: 14px 16px;
}

.lesson-list .list-group-item:first-child {
  border-top: none;
}

.stat-card {
  border: none;
  border-radius: 12px;
  padding: 20px;
}

.stat-card .stat-icon {
  width: 48px;
  height: 48px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 24px;
}

.empty-state {
  padding: 60px 20px;
  text-align: center;
  color: var(--text-muted);
}

.empty-state i {
  font-size: 64px;
  margin-bottom: 16px;
}

.video-container {
  position: relative;
  width: 100%;
  background: #000;
  border-radius: 12px;
  overflow: hidden;
}

.video-container video {
  width: 100%;
  max-height: 500px;
}

.pdf-container {
  height: 70vh;
  border: 1px solid var(--border);
  border-radius: 8px;
  overflow: hidden;
}

.pdf-container iframe {
  width: 100%;
  height: 100%;
  border: none;
}

.quiz-option {
  border: 2px solid var(--border);
  border-radius: 12px;
  padding: 16px;
  cursor: pointer;
  transition: all 0.2s;
}

.quiz-option:hover {
  border-color: var(--primary-light);
}

.quiz-option.selected {
  border-color: var(--primary);
  background: rgba(26,35,126,0.05);
}

.quiz-timer {
  font-size: 24px;
  font-weight: bold;
  color: var(--primary);
}

.quiz-timer.warning {
  color: var(--error);
  animation: pulse 1s infinite;
}

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

.profile-avatar {
  width: 100px;
  height: 100px;
  border-radius: 50%;
  background: var(--primary);
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 40px;
  font-weight: bold;
  margin: 0 auto;
}

.certificate-card {
  border: none;
  border-radius: 12px;
}

.footer {
  background: var(--primary);
  color: white;
  padding: 20px 0;
  margin-top: 60px;
}

/* Loading spinner */
.loading {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 40px;
}

.spinner {
  width: 40px;
  height: 40px;
  border: 4px solid var(--border);
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

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

/* Alert animations */
.alert-dismissible {
  animation: slideIn 0.3s ease;
}

@keyframes slideIn {
  from { transform: translateY(-10px); opacity: 0; }
  to { transform: translateY(0); opacity: 1; }
}

.price-original {
  text-decoration: line-through;
  color: var(--text-muted);
  font-size: 14px;
}

.price-current {
  color: var(--accent);
  font-size: 24px;
  font-weight: bold;
}

.navbar-brand i {
  margin-right: 8px;
}