JSFiddle - React, Tailwind, and code Playground

HTML

<div id="parent">
    <div id="child">
        <p>CHILD ELEMENT</p>
    </div>
</div>

CSS

#parent {
    border: solid 1px red;
    float: left;
    height: 150px;
    position:relative;
}
#child {
    background:green;
    position: absolute;
    top:100%;
//    transform: translateY(-100%);
    width: auto;
}
p {
    color:white;
    white-space: nowrap;
}