JSFiddle - React, Tailwind, and code Playground

HTML

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

CSS

div#container {
    border: 1px solid #000000;
    width: 500px;
    height: 200px;
}
div#inner {
    border: 1px solid #FF0000;
    width: 200px;
    height: 100px;
    margin: 0 auto;
}