JSFiddle - React, Tailwind, and code Playground

HTML

<div class="outer">
    <div class="inner">
    </div>
</div>

CSS

.outer {
    height: 500px;
    width: 300px;
    background: blue;
    position: relative;
}

.inner {
    width: 80%;
    height: 200px;
    background:green;
    position: absolute;
    margin-left: 10%;
    margin-right: 10%;
    margin-top: 10%;
    margin-bottom: 0;
}