JSFiddle - React, Tailwind, and code Playground

HTML

<div class="block1"></div>
<div class="block2"></div>

CSS

.block1 {
    width: 500px;
    height: 500px;
    background-color: red;
    border: 1px solid black;
    position: absolute;
}
.block2 {
    width: 500px;
    height: 500px;
    background-color: green;
    border: 1px solid black;
    position: relative;
    z-index: 10;
}