JSFiddle - React, Tailwind, and code Playground

HTML

<div id="outer">
    <div id="inner">
        <div id="left"></div>
        <div id="top"></div>
    </div>
</div>

CSS

#left,#top {
    position:absolute;
    border:solid black 2px;
    width:100px;
    height:100px;
}
#left {
    margin-left:-30px;
}
#top {
    margin-left:100px;
    margin-top:-30px;
}
#inner {
    position:absolute;
    top:70px;
    left:0;
    width:300px;
    height:200px;
    border:solid 2px red;
}
#outer {
    position:absolute;
    top:0;
    left:100px;
    width:304px;
    height:100%;
    border:solid 2px green;
    overflow: hidden;
}