JSFiddle - React, Tailwind, and code Playground

HTML

<div id="outer">
    <div id="inner">asdasd
    </div>
</div>

CSS

#outer {
    position: relative;
    width: 300px;
    height: 300px;
    outline: 1px solid red;
}

#inner {
    position: absolute;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
    outline: 1px solid red;
}