JSFiddle - React, Tailwind, and code Playground

HTML

<html>


<body>
<ul>
<li><a href="">Test</a></li>
<ul>
<li><a href="">Sub1</a></li>
<li><a href="">Sub2</a></li>
</ul>
<li>Test2</li>
</ul>
</body>
</html>

CSS

body ul ul{
  display:none;
}

body ul li:hover + ul {
  display:block;
}