JSFiddle - React, Tailwind, and code Playground

HTML

<div id="box1">
    <div id="box2"></div>
</div>

CSS

#box1{
display: block;
background:red;
background-size: 100%;
position: relative;
padding-bottom: 60%;
}

#box2{
    display:block;
    background:blue;
    position:absolute;
    height:70px;
    width:70px;
    right:50%;
    top:50%;
  }