JSFiddle - React, Tailwind, and code Playground

by LuckyCat

HTML

<div class="test">
  <div class="tt">

  </div>
  </div>

CSS

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
.test {
  width: 300px;
  height: 300px;
}
.tt {
  background: yellow;
  margin-top: -100%;
  padding: 100%;
}