<!doctype html>
<title>CSS Test Reference</title>
<link rel="author" href="mailto:emilio@crisal.io" title="Emilio Cobos Álvarez">
<link rel="author" href="https://mozilla.org" title="Mozilla">
<style>
  div::first-letter {
    color: lime;
    background-color: lime;
  }
</style>
<div>
  A letter
</div>