JSFiddle - React, Tailwind, and code Playground

HTML

<div class="main">
	<div class="parent">
		<div class="child"></div>
	</div>
</div>

CSS

.main {
    width : 400px;
    height: 400px;
    border :1px solid black;
}
.parent {
    width: 100px;
    height: 100px;
    background: #e3e3e3;
    z-index: 1;
}
.child {
    width : 200px;
    height: 200px;
    background: red;
    z-index: -1;
    position: relative;
}