.simplescrollup__button {
    position: fixed;
    bottom: 3rem;
    right: 3rem;
    transition: 1s all;
    z-index: 10000;
    color: #fff;
  }
  .simplescrollup__button--show { transform: translateX(0); }
  .simplescrollup__button--hide { transform: translateX(100px); }