JSFiddle - React, Tailwind, and code Playground

HTML

<ul class="horizontal">
    <li>First List
    <ul class="ul1">
        <li>first</li>
        <li>Second</li>
        <li>Third</li>
    </ul>
    <li>Second List
    <ul>
        <li>first</li>
        <li>Second</li>
        <li>Third</li>
    </ul>
</ul>

CSS

.horizontal >li {
  float: left;
  list-style: none;
  margin: 10px;
}

li > ul:nth-child(1) {
    color:RED
}