JSFiddle - React, Tailwind, and code Playground

HTML

<body>
  
  <div class="navbar">
    <ul>
      <li><a href="#">One</a></li>
      <li><a href="#">One</a></li>
      <li><a href="#">One</a></li>
    </ul>
  </div>
  
  <div class="dropdown-content">
    <ul>
      <li><a href="#">One</a></li>
      <li><a href="#">One</a></li>
      <li><a href="#">One</a></li>
    </ul>
  </div>
  
</body>

CSS

.dropdown-content {
  display: none;
}

.navbar>li, a:hover + .dropdown-content {
  display: block;
}