JSFiddle - React, Tailwind, and code Playground

HTML

<div class="outer-container">
   <div class="inner-container">
     <div class="centered-content">
        Center this!
     </div>
   </div>
</div>

CSS

.outer-container {
    display: table;
    width: 80%;
    height: 120px;
    background: #ccc;
}

.inner-container {
    display: table-cell;
    vertical-align: middle;
    text-align: center;
}

.centered-content {
    display: inline-block;
    text-align: left;
    background: #fff;
    padding : 20px;
    border : 1px solid #000;
}