JSFiddle - React, Tailwind, and code Playground

HTML

<div class="content">
    <div class="area-a"></div>
    <div class="area-b"></div>
    <div class="area-c"></div>
    <div class="area-d"></div>
</div>

CSS

.content {
            position: fixed;
            left: 50px;
            top: 50px;
            right: 50px;
            bottom: 50px;
            background-color: lightcyan;
        }

.area-a {
    height: 30px;
    background-color: lightcoral;
}
.area-b{
    height:50px;
    background-color:lightgreen;
    position:absolute;
    left:0px;
    right:0px;
    top:30px;
}

.area-c {
    background-color: lightgrey;
    height: 100px;
    position:absolute;
    left:0px;
    right:0px;
    bottom:50px;
}

.area-d {
    height: 50px;
    background-color: brown;
    position: absolute;
    bottom: 0px;
    left: 0px;
    right: 0px;
}