/* 经典回顾 - UI Style 1 - Layout F */

.video-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 4px 12px rgba(0,0,0,0.15);
}

.video-grid .video-card h3 a:hover {
  color: #3498db;
  transition: color 0.3s;
}

button, .btn {
  background: #3498db;
  color: #fff;
  border: none;
  padding: 0.6rem 1.2rem;
  border-radius: 4px;
  cursor: pointer;
  font-size: 1rem;
  transition: background 0.3s;
}

button:hover, .btn:hover {
  background: #2980b9;
}

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

  main {
    padding: 0 0.5rem !important;
  }

  h1 {
    font-size: 1.5rem !important;
  }

  h2 {
    font-size: 1.2rem !important;
  }
}

/* 回到顶部按钮 */
#back-to-top {
  display: none;
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  background: #3498db;
  color: #fff;
  width: 50px;
  height: 50px;
  border-radius: 50%;
  text-align: center;
  line-height: 50px;
  font-size: 1.5rem;
  cursor: pointer;
  box-shadow: 0 2px 8px rgba(0,0,0,0.2);
  z-index: 1000;
  transition: background 0.3s;
}

#back-to-top:hover {
  background: #2980b9;
}

#back-to-top.show {
  display: block;
}