JSFiddle - React, Tailwind, and code Playground

HTML

<div id='new-stack'></div>
<div id='blue'></div>

CSS

#blue {
  z-index: 2;
  height: 50px;
  width: 50px;
  background: #688ef0;
}
#new-stack {
  z-index: 1;
  background: #eee;
  position: absolute;
  top: 0;
  height: 50px;
  width: 50px;  
}