#scrollToTopBtn {
    display: none;
    position: fixed;
    bottom: 25px;
    right: 25px;
    width: 50px;
    height: 50px;
    background-color: #000;
    color: #fff;
    border: none;
    font-size: 24px;
    cursor: pointer;
    z-index: 999;
  }
  
  #scrollToTopBtn.show {
    display: block;
  }