JSFiddle - React, Tailwind, and code Playground

HTML

<div class="rel-block">
    
    <div class="abs-block"></div>
    
</div>

<div class="red"></div>

CSS

.rel-block{
    position: relative;
    width: 100%;
    background: #ccc;
    height: 250px;
}

.abs-block{
    position: absolute;
    width: 100%;
    height: 250px;
    background: #000;
}

.red{
    width: 100%;
    height: 100px;
    background: red;
}