JSFiddle - React, Tailwind, and code Playground

HTML

<div id="outer" style="width:100%;">  
    <div id="inner">Foo foo</div>
</div>

CSS

div#outer {
    height: 120px;
    background-color: red;
}

div#inner {
    width: 50%;
    height: 100%;
    background-color: green;
    margin: 0 auto;
    text-align:center; 
    line-height: 120px;
}