JSFiddle - React, Tailwind, and code Playground

HTML

<div id="menu">
  <ul>
    <li>
      <a href="javascript: void(0)">
      Lalalalal
      </a>
      <ul>
        <li>
          <a href="javascript: void(0)"><span>Link 1</span></a>
          <a href="javascript: void(0)"><span>Link 2</span></a>
          <a href="javascript: void(0)"><span>Link 3</span></a>
        </li>
      </ul>
    </li>
  </ul>
</div>

CSS

#menu ul li > ul {
  visibility: hidden;
}
#menu ul li:focus > ul {
  visibility: visible !important;
}