JSFiddle - React, Tailwind, and code Playground

HTML

<div id="container">
  <div id="content">
  </div>
</div>

CSS

#container {
  position: fixed;
  background: lightblue;
  top: 0; bottom: 0;
  left: 0; right: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: auto;
}

#content {
  border: 1px solid green;
  /* uncomment the hack below to get desired behavior */
  /* margin: auto */
}

JavaScript

document.getElementById('content').innerHTML = [...Array(100).keys()].join('<br>')