JSFiddle - React, Tailwind, and code Playground

HTML

<div class="parent">
    <div class="child">
    </div>
</div>

CSS

div.parent {
    background-color:yellow;
    padding-left:20px;
    padding-right:20px;
    width:200px;
    height:200px;
}
div.child {
    background-color:red;
    width:50%;
    height:50%;
}