JSFiddle - React, Tailwind, and code Playground

HTML

<div id="foo">
    <div id="bar">aaa</div>    
</div>

CSS

#foo{
    background-color: #00f;
    //border: 1px solid;
    //overflow:auto;
}

#bar{
    margin-top: 10px;
    background-color: #f00;
}