JSFiddle - React, Tailwind, and code Playground

by Imabot

HTML

<div class="square"></div>
<div class="square with-circle"></div>
<div class="square with-circle-hover"></div>

CSS

body { display: flex; }

.square {
  background-color: #6297CB;
  border: 3px solid #468189;
  width: 30vmin;
  height: 30vmin;
  margin: 5px;  
}

.square.with-circle-hover:hover::before,
.square.with-circle::before{
  content: '';
  display: inline-block;
  left: 20%;
  top: 20%;
  width: 60%;
  height: 60%;
  border-radius: 100%;
  background-color: #00CC66;
  position: relative;
}