JSFiddle - React, Tailwind, and code Playground

HTML

<nav class="nav"></nav>

<div class="navWrap">
  <nav class="nav"></nav>
</div>

<div class="navWrap">
  <nav id="nav"></nav>
</div>

CSS

.nav {
  padding: 20px;
  background-color: red;
}

#nav {
  padding: 20px;
  background-color: red;
}


.navWrap .nav {
  background-color: #000;
}