JSFiddle - React, Tailwind, and code Playground

HTML

<div id="outer">
    <div id="inner">
        <div id="inner-inner"></div>
    </div>
</div>

CSS

#outer {
    min-width: 2000px; 
    min-height: 1000px; 
    background: #3e3e3e; 
    position:relative
}

#inner {
    left: 1%; 
    top: 45px; 
    width: 50%; 
    height: auto; 
    position: absolute; 
    z-index: 1;
}

#inner-inner {
    background: #efffef;
    position: absolute; 
    height: 400px; 
    right: 0px; 
    left: 0px;
}