JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">
  <div class="inner"></div>
</div>

CSS

html,body {margin:0}

.container {
  background: red;
  height: 500px;
}

.inner {
  /*margin-top: 100px;*/
  height: 50px;
  background: yellow;
}