Scroll to top button fade in

In your footer script change it to this code

<script src="//ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/5.12.1/js/all.min.js" crossorigin="anonymous"></script>
<button onclick="topFunction()" id="myBtn" title="Go to top">
    <i class="fa fa-chevron-up"></i>
</button>

<script>
   window.onscroll = function() {scrollFunction()};

   function scrollFunction() {
      if (document.body.scrollTop > 20 || document.documentElement.scrollTop > 20) {
         document.getElementById("myBtn").style.opacity = "1";
      } else {
         document.getElementById("myBtn").style.opacity = "0";
      }
   }

   function topFunction() {
      $('html,body').animate({ scrollTop: 0 }, 1000);
   }
</script>

And in the custom css, modify accordingly

#myBtn {
    width: 50px;
    height: 50px;
    transition: opacity 0.5s ease-in-out;
    position: fixed;
    bottom: 20px;
    right: 30px;
    z-index: 99;
    border: none;
    outline: none;
    font-size: 25px !important;
    color: #fff;
    cursor: pointer;
    padding: 10px 10px 10px 11px;
    border-radius: 0%;
    box-shadow: 1px 1px 2px #000;
    background-color: #a1d941;
    opacity: 0;
}

I made the changes you suggested but now the scroll button isn't appearing. Any thoughts?

I made a mistake on this line. please change it to 0, also remove !important in opacity css of

#myBtn

That did it. It looks great. Couldn't figure it out.

Thank you so much.