@keyframes fadeIn {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

.video-card, .list-card, .related-card {
  animation: fadeIn 0.5s ease-out;
}

.video-card:nth-child(1), .list-card:nth-child(1) { animation-delay: 0.05s; }
.video-card:nth-child(2), .list-card:nth-child(2) { animation-delay: 0.1s; }
.video-card:nth-child(3), .list-card:nth-child(3) { animation-delay: 0.15s; }
.video-card:nth-child(4), .list-card:nth-child(4) { animation-delay: 0.2s; }

.ui-style-7 header {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

.ui-style-7 .section-header h2::before {
  content: '▶ ';
  color: #667eea;
}

.ui-style-7 a {
  transition: all 0.3s ease;
}

.ui-style-7 .video-card:hover,
.ui-style-7 .list-card:hover,
.ui-style-7 .related-card:hover {
  border-left: 4px solid #667eea;
}

.back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  background: #667eea;
  color: white;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  display: none;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  box-shadow: 0 4px 12px rgba(102, 126, 234, 0.4);
  transition: all 0.3s ease;
  z-index: 1000;
}

.back-to-top:hover {
  background: #764ba2;
  transform: translateY(-4px);
}

.back-to-top.show {
  display: flex;
}

@media (max-width: 768px) {
  .back-to-top {
    bottom: 1rem;
    right: 1rem;
    width: 40px;
    height: 40px;
  }
}