JSFiddle - React, Tailwind, and code Playground

HTML

<div class="box"></div>

CSS

.box{
	width: 350px;
	height: 350px;
	background: #555;
	position: absolute;
	top: 50px;
	left: 200px;
	z-index: 10;
}
.box::before{
	content: "";
	background: #A60000;
	width: 300px;
	height: 300px;
	position: absolute;
	top: 25px;
	left: -150px;
	z-index: 1;
}
.box::after{
	content: "";
	background: #02047A;
	width: 300px;
	height: 300px;
	position: absolute;
	top: 25px;
	left: 200px;
	margin: auto;
	z-index: 1;
}