img {
    max-width: 100%;
  }
  
  .relative {
    position: relative;
  }
  
  .影片背景 {
    position: relative;
    z-index: 2;
  }
  
  .video1 {
    position: absolute;
    left: 0%;
    top: 0%;
    width: 100%;
    z-index: 1;
    display: block;
  }
  
  .video2 {
    width: 100%;
    display: block;
  }
  
  .video10 {
    width: 100%;
    display: block;
  }
  
  .共用1 {
    position: absolute;
    left: 0%;
    top: 0%;
    width: 100%;
    z-index: 5;
  }
  
  .共用2 {
    position: absolute;
    left: 0%;
    top: 0%;
    width: 100%;
    z-index: 2;
  }