JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">
<div class="item"></div>
</div>

CSS

.container{
    position: relative;
    width: 300px;
    height: 300px;
    background-color: red;
    margin:auto;
}

.item{
    position: absolute;
    width: 100px;
    height: 100px;
    background-color: blue;
    left:0;
    right:0;
    top:0;
    bottom:0;
    margin: auto;
}