JSFiddle - React, Tailwind, and code Playground

HTML

<div class="one">
  <div class="two"></div>
</div>

CSS

.one{
  width: 200px;
  height: 200px;
  position: relative;
  background: #000;
  padding: 10px;
}

.two{
  position: absolute;
  width: 100%;
  height: 100%;
  background: red;
  left:10px;
  bottom:10px;
}