/* A 布局变体 */
body.ui-style-11 {
  --primary-color: #1890ff;
  --secondary-color: #722ed1;
  --accent-color: #13c2c2;
  --text-color: #333;
  --bg-color: #f5f5f5;
}

.video-card:hover {
  border-color: var(--primary-color);
}

.section h2 {
  position: relative;
}

.section h2::before {
  content: '';
  position: absolute;
  left: 0;
  bottom: 0;
  width: 60px;
  height: 3px;
  background: linear-gradient(90deg, var(--primary-color), var(--accent-color));
}

@media (max-width: 768px) {
  .video-grid {
    grid-template-columns: 1fr;
  }

  .container {
    padding: 15px;
  }

  .section {
    padding: 20px 15px;
  }
}

.back-to-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  width: 50px;
  height: 50px;
  background: var(--primary-color);
  color: white;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  opacity: 0;
  transition: opacity 0.3s;
  z-index: 1000;
}

.back-to-top.show {
  opacity: 1;
}

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