JSFiddle - React, Tailwind, and code Playground

HTML

<div class="layer-1">
    <span class="layer-2"></span>
</div>

CSS

.layer-1 {
    width: 100px;
    height: 100px;
    background: red;
    position: relative;
    z-index: 1;
}
.layer-2 {
    background: blue;
    position: absolute;
    z-index:2;
    top: 0;
    bottom: 0;
    left: 0;
    right: 0;
}