#parallax__top {
    position: fixed;
    right: -200px;
    bottom: -200px;
    z-index: 10000;
    transform: translate(-50%);
    width: 40px;
    height: 40px;
    background: rgba(39, 66, 200, 0.4);
    text-align: center;
    line-height: 40px;
    color: #fff;
    border-radius: 50%;
    cursor: pointer;
    transition: all 0.3s;
  }
  #parallax__top.show {
    right: 50px;
    bottom: 50px;
  }
  #parallax__top:hover {
    background: #fff;
    color: #000;
  }