#back-top-button {
    display: inline-block;
    background-color: #fff;
    width: 50px;
    height: 50px;
    text-align: center;
    border-radius: 4px;
    position: fixed;
    bottom: 30px;
    right: 30px;
    transition: background-color .3s, opacity .5s, visibility .5s;
    opacity: 0;
    visibility: hidden;
    z-index: 1000;        
    background-color: #F92C8B;
    border: 1px solid white;
    color: white;
  }

  #back-top-button::after {    
    font-family: FontAwesome;
    font-weight: normal;
    font-style: normal;
    font-size: 2em;
    line-height: 50px;
    color:red;
  }

  #back-top-button:hover {
    cursor: pointer;    
    background-color: #B12CD6;
  }

  #back-top-button:active {
    background-color: red;
  }

  #back-top-button.show {
    opacity: 1;
    visibility: visible;
  }