JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.1.1/jquery.min.js"></script>

<body>
  <div class="custom-cursor">
  </div>
</body>

CSS

body {
  background: red;
  height: 1000vh;
  position: relative;
}

.custom-cursor {
  position: absolute;
  width: 30px;
  height: 30px;
  border-radius: 100%;
  z-index: 9999;
  background-color: yellow;
  backface-visibility: hidden;
  pointer-events: none;
  transform: translate(-50%, -50%); // Center over cursor
  transition: width .3s ease-in-out, height .3s ease-in-out;
}

JavaScript

// vars
var xMousePos = 0;
var yMousePos = 0;
var lastScrolledLeft = 0;
var lastScrolledTop = 0;
var $cursor = $('.custom-cursor');

// Follow cursor
$('body').on('mousemove', function(e) {
  var parentOffset = $(this).offset();
  var relX = e.pageX - parentOffset.left;
  var relY = e.pageY - parentOffset.top;
  xMousePos = event.pageX;
  yMousePos = event.pageY;

  $cursor.css({
    left: relX,
    top: relY
  });
});
$(window).scroll(function(event) {
  if (lastScrolledLeft != $(document).scrollLeft()) {
    xMousePos -= lastScrolledLeft;
    lastScrolledLeft = $(document).scrollLeft();
    xMousePos += lastScrolledLeft;
  }
  if (lastScrolledTop != $(document).scrollTop()) {
    yMousePos -= lastScrolledTop;
    lastScrolledTop = $(document).scrollTop();
    yMousePos += lastScrolledTop;
  }
  //console.log("x = " + xMousePos + " y = " + yMousePos);
  $cursor.css({
    left: xMousePos - 7.5,
    top: yMousePos - 7.5
  });
});