JSFiddle - React, Tailwind, and code Playground

HTML

<ol class=top>
  <li>Top item
  
    <ol>
      <li>Sub</li>
      <li>list</li>
      <li>item.</li>
    </ol>
  </li>
</ol>

CSS

.top > li {
  text-decoration: underline;
}

.top ol li {
  text-decoration: none;
}