JSFiddle - React, Tailwind, and code Playground

HTML

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

CSS

.parent{
    width:300px;
    height:300px;
    background:red;
  
}
.child{
    width:100px;
    height:100px;
    background:green;
    margin-left:20px;  
}