/* 响应式优化与移动端单行导航 */
@media (max-width: 768px) {
  .header nav {
    display: flex !important;
    flex-wrap: nowrap !important;
    overflow: visible !important;
    justify-content: space-between;
  }
  .header nav a {
    flex: 1 1 0 !important;
    min-width: 0 !important;
    white-space: nowrap !important;
    overflow: hidden !important;
    text-overflow: ellipsis !important;
  }
  .video-grid {
    grid-template-columns: 1fr !important;
  }
}