JSFiddle - React, Tailwind, and code Playground

HTML

<div id="big"></div>
<div id="small"> 
     <div></div>
</div>

CSS

#big {
    width: 600px;
    height: 800px;
    background: green;
    position: relative;
}
#small{
    bottom: 0px;
    position: absolute;
    width: 600px;
}
#small div{
    background:red;
    height: 200px;
    margin: auto;
    position: relative;
    width: 200px;
}