JSFiddle - React, Tailwind, and code Playground

by Eugeny Venegrad

HTML

<html data-dark>

  <div class="block"></div>

</html>

<div class="block"></div>

CSS

/* core.css */
:root {
  --main-bg-color: green; 
}

.block {
  width: 100px;
  height: 100px;
  background-color: var(--main-bg-color);
}

html[data-dark]:root {
  --main-bg-color: red; 
}