JSFiddle - React, Tailwind, and code Playground

HTML

<div class="MainContainerDIV" style="width: 100%; height: 200px;">This is the main div
    <div class="SubDIV" >
        <p>this is the sub div</p>
    </div>
</div>

CSS

.SubDIV {
    position: relative; top:50px;
    background: red;
    width: 100%;
}
.MainContainerDIV {
    background: blue;
}