JSFiddle - React, Tailwind, and code Playground

HTML

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

CSS

html, body {
    height: 100%;
}
#container {
    width: 100%;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
}
#contained {
    width: 50px;
    height: 50px;
    background-color: red;
}