JSFiddle - React, Tailwind, and code Playground

HTML

<header>Logo and hamburger</header>
<nav>Nav list</nav>

CSS

html {
	font-size: 56.25%;
}

header {
  line-height: 6.3rem;
  border-bottom: 1px solid black;
  font-size: 2rem;
}

nav {
  position: absolute;
  top: 6.3rem;
  left: 0;
  right: 0;
  background-color: yellow;
  font-size: 2rem;
}