JSFiddle - React, Tailwind, and code Playground

HTML

<div id="outer">
    <div id="inner">
        Nah nah nah
        
    </div>
</div>

CSS

#outer {
    width: 300px;
    background: red;
    border-radius:20px;
}

#inner {
    background:blue; margin:0 0px;
}