.scroll-to-top {
  position: fixed;
  bottom: 31px;
  right: 31px;
  display: none;
  cursor: pointer;
  z-index: 1000;
}
  #scrollFollower {
    position: fixed;
    bottom: 31px;
    right: 31px;
    animation: scrollFollow 2s infinite;
  }
  @keyframes scrollFollow {
    from {
      bottom: 31px;
    }
    to {
      bottom: 19px; /* 上下跳动距离，31px则相同不跳 */
    }
  }