JSFiddle - React, Tailwind, and code Playground

HTML

<div id="outher">
	<div id="inner">
		
	</div>
</div>

CSS

#outher {
	width: 1000px;
	height: 1000px;
	background-color: #ccc;
}

#inner {
	width: 400px;
	height: 300px;
	background-color: #090;
	left: 50%;
}