JSFiddle - React, Tailwind, and code Playground

HTML

<div class="div1">
  <div class="div2">
  
  </div>
</div>

CSS

body {
  background-color: black;
}

.div1 {
  position: absolute;
  width: calc(100% - 22rem);
  min-height: calc(100% - 7.75rem);
  background-color: white;
}

.div2 {
  width: 100%;
  background-color: green;
  height: 100%;
  position: absolute;
}