JSFiddle - React, Tailwind, and code Playground

HTML

<header></header>
<div class="content">

</div>

CSS

* {
  padding: 0;
  margin: 0;
}

header {
  height: 60px;
  background: pink;
 }

.content {
  height: calc(100vh - 60px);
  background: blue;
}