Remove a "back to top" Button from Mobile View

Site URL: https://www.neemaproject.org/

Hello! Would anyone be able to help me remove a "back to top" button from mobile view? Or edit it so that it works on mobile? The website is www.neemaproject.org and the code injected on the main home page is this: 

<style>
  .back-to-top {
    background-color: #000000;
    color: #FFFFFF;
    opacity: 0;
    transition: opacity .6s ease-in-out;
    z-index: 999;
    position: fixed;
    right: 20px;
    bottom: 20px;
    width: 50px;
    height: 50px;
    box-sizing: border-box;
    border-radius: 50%;
  }

  a.back-to-top {
    font-weight: 1000;
    letter-spacing: 2px;
    font-size: 12px;
    text-transform: uppercase;
    text-align: center;
    line-height: 1.6;
    padding-left: 2px;
    padding-top: 16px;
  }

  .back-to-top:hover, .back-to-top:focus, .back-to-top:visited {
    color: #FFFFFF;
  }

  .back-to-top.show {
    opacity: 1;
  }
</style>

<!-- Adds the back to top link to your website -->
<a href="#" id="back-to-top" class="back-to-top" style="display: inline;">TOP</a>

<!-- Fades in the button when you scroll down -->
<script>
  var link = document.getElementById("back-to-top");
  var amountScrolled = 250;

  window.addEventListener('scroll', function(e) {
      if ( window.pageYOffset > amountScrolled ) {
          link.classList.add('show');
      } else {
          link.className = 'back-to-top';
      }
  });

<!-- Scrolls to Top -->
  link.addEventListener('click', function(e) {
      e.preventDefault();

      var distance = 0 - window.pageYOffset;
      var increments = distance/(500/16);
      function animateScroll() {
          window.scrollBy(0, increments);
          if (window.pageYOffset <= document.body.offsetTop) {
              clearInterval(runAnimation);
          }
      };
      // Loop the animation function
      var runAnimation = setInterval(animateScroll, 16);
  });
</script>

Add to Design > Custom CSS

/* remove back to top mobile */
@media screen and (max-width:767px) {
.back-to-top {
	display: none !important;
	}
}

Or follow this guide to add back to top, works on both mobile & desktop.