JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://rawgithub.com/soulwire/fit.js/master/fit.js"></script>
<div id="div">
  <div id="smoker">
  
  </div>
</div>

CSS

html, body {
    margin: 0;
    height: 100%;
    width: 100%;
}

#smoker {
    background: blue;
    height: 1000px;
    width: 400px;
}

JavaScript

var div = document.getElementById("div");
fit(div, document.body, {watch: true});