JSFiddle - React, Tailwind, and code Playground

HTML

<div>
    <span></span>
</div>

CSS

body, html {
    height: 100%;
    margin: 0;
    background: green;
}
div {
    height: 100%;
    max-height: 350px;
    width: 100px;
    background: red;
    position: absolute;
}
div span {
    background: #f0f;
    display: block;
    height: 100%;        
    width: 50px;
}