JSFiddle - React, Tailwind, and code Playground

HTML

<div class="test"></div>

CSS

body {
  height: 2000px;
}
.test {
  background: red;
  height: 100px;
  position: absolute;
  right: 100px;
  top: 100px;
  -webkit-transition: all 1s;
  -moz-transition: all 1s;
  -ms-transition: all 1s;
  -o-transition: all 1s;
  transition: all 1s;
  width: 100px;
}

JavaScript

(function() {
  var elem = document.querySelector('.test');
  window.addEventListener('scroll', function() {
    elem.style.marginTop = this.pageYOffset + 'px';
  });
})();