JSFiddle - React, Tailwind, and code Playground

HTML

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

CSS

.parent {
  background-color: black;
  width: 200px;
  height: 20px;
  position: absolute;
  z-index: 10;
}

.child {
  background-color: RED;
  width: 300px;
  height: 20px;
  position: absolute;
  z-index: 1;
}

.normal {
  position: absolute;
  z-index: 2;
  width: 300px;
  height: 20px;
  background: green;
  
}