JSFiddle - React, Tailwind, and code Playground

HTML

<div class='wrap'>
    <div class='outer'>
        <div class='inner'>
    </div>
    </div>
</div>

CSS

.wrap {
    border: 1px solid black; 
    text-align: center;
}

.outer {
    border: 1px solid blue;
    display: inline-block;
    margin: 0 auto;
}

.inner {
    border: 1px solid green;
    width: 50px;
    height: 50px;
}