JSFiddle - React, Tailwind, and code Playground

HTML

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

CSS

.outer {
    width: 200px;
    height: 50px;
    background-color: blue;
}

.inner {
    width: 100%;
    height: 100%;
    margin: 0 10%;
    background-color: red;
}