JSFiddle - React, Tailwind, and code Playground

by dholbert

HTML

The alert() popup will tell you how big 1rem is.
<div id="inspectMe">

</div>

CSS

#inspectMe {
  width: 1rem;
  height: 1rem;
  background: blue;
}

JavaScript

alert("1rem is " + window.getComputedStyle(inspectMe, "").width);