/* Modern Lesson Cards Styling */
.lessons-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 24px;
  padding: 24px;
  margin: 0 auto;
  max-width: 1200px;
}

.lesson-card {
  position: relative;
  background: linear-gradient(135deg, #ffffff 0%, #f8faff 100%);
  border-radius: 16px;
  padding: 24px;
  transition: all 0.3s ease;
  border: 1px solid rgba(0, 128, 255, 0.1);
  display: flex;
  align-items: flex-start;
  gap: 16px;
  cursor: pointer;
  overflow: hidden;
  box-shadow: 0 4px 12px rgba(0, 128, 255, 0.06),
              0 1px 3px rgba(0, 0, 0, 0.08);
}

.lesson-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(90deg, #0080FF, #00C2FF);
  opacity: 0;
  transition: opacity 0.3s ease;
}

.lesson-card:hover:not(.locked) {
  transform: translateY(-4px);
  box-shadow: 0 12px 28px rgba(0, 128, 255, 0.12),
              0 2px 4px rgba(0, 0, 0, 0.05);
  background: linear-gradient(135deg, #ffffff 0%, #f0f7ff 100%);
}

.lesson-card:hover:not(.locked)::before {
  opacity: 1;
}

.lesson-card.locked {
  background: #F8FAFC;
  cursor: not-allowed;
  opacity: 0.95;
  position: relative;
}

.lesson-number {
  background: linear-gradient(135deg, #f0f7ff 0%, #e6f0ff 100%);
  color: #0080FF;
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 12px;
  font-size: 20px;
  font-weight: 600;
  flex-shrink: 0;
  transition: all 0.3s ease;
  border: 1px solid rgba(0, 128, 255, 0.15);
  box-shadow: 0 2px 4px rgba(0, 128, 255, 0.1);
}

.lesson-card:hover:not(.locked) .lesson-number {
  background: linear-gradient(135deg, #0080FF 0%, #00A3FF 100%);
  color: white;
  border-color: transparent;
}

.lesson-card.locked .lesson-number {
  background: linear-gradient(135deg, #f8fafc 0%, #f1f5f9 100%);
  color: #94A3B8;
  border: 1px solid rgba(148, 163, 184, 0.2);
  box-shadow: none;
}

.lesson-details {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.lesson-title {
  color: #1E293B;
  font-size: 18px;
  font-weight: 600;
  margin: 0;
  line-height: 1.4;
  transition: all 0.3s ease;
  position: relative;
  display: inline-block;
}

.lesson-title::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 2px;
  background: linear-gradient(90deg, #0080FF, #00C2FF);
  transition: width 0.3s ease;
}

.lesson-card:hover:not(.locked) .lesson-title::after {
  width: 100%;
}

.lesson-desc {
  color: #64748B;
  font-size: 14px;
  margin: 8px 0 0 0;
  line-height: 1.6;
  transition: color 0.3s ease;
}

.lesson-card:hover:not(.locked) .lesson-desc {
  color: #475569;
}

.lesson-lock {
  position: absolute;
  top: 16px;
  right: 16px;
  color: #94A3B8;
  font-size: 24px;
  background: linear-gradient(135deg, #f8fafc 0%, #f1f5f9 100%);
  padding: 8px;
  border-radius: 50%;
  box-shadow: 0 2px 8px rgba(148, 163, 184, 0.2);
  transition: all 0.3s ease;
  border: 1px solid rgba(148, 163, 184, 0.1);
}

.lesson-card.locked:hover .lesson-lock {
  color: #64748B;
  transform: scale(1.1);
}

.lesson-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 4px;
  height: 100%;
  background: #0080FF;
  transform: scaleY(0);
  transition: transform 0.3s ease;
}

.lesson-card:hover:not(.locked)::before {
  transform: scaleY(1);
}

/* Progress indicator */
.lesson-card::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 3px;
  background: linear-gradient(90deg, #0080FF 0%, #00C2FF 100%);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.3s ease;
}

.lesson-card:hover:not(.locked)::after {
  transform: scaleX(1);
}

/* Additional hover effects */
.lesson-card:hover:not(.locked) .lesson-title {
  color: #0080FF;
}

.lesson-card:active:not(.locked) {
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 128, 255, 0.08);
}

/* Responsive adjustments */
@media screen and (max-width: 768px) {
  .lessons-grid {
    grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
    padding: 16px;
    gap: 16px;
  }

  .lesson-card {
    padding: 16px;
  }

  .lesson-number {
    width: 40px;
    height: 40px;
    font-size: 16px;
  }
}