JSFiddle - React, Tailwind, and code Playground

HTML

<script src="bootstrap"></script>
<div id="first">
    <div id="second">
    
    </div>
</div>

CSS

#first {
  position: relative;
  width: 200px;
  height: 200px;
  border-radius: 50%;
  background-color: #94b8b8;
}
#second {
  position: absolute;
  width: 15%;
  height: 15%;
  left:42.5%;
  top:42.5%;
  border-radius: 50%;
  background-color: blue;
}