#top-cover{
    position: fixed;
    cursor: pointer;
    display: block;
    z-index: 50;
    text-align: center;
  }
  @media screen and (min-width: 768px) {
    #top-cover{
      width: 60px;
      height: 60px;
      bottom: 40px;
      right:26px;
    }
  }
  @media screen and (max-width: 767px) {
    #top-cover{
      width: 60px;
      height: 60px;
      bottom:110px;
      right:9px;
    }
  }