JSFiddle - React, Tailwind, and code Playground

HTML

<div id="foo">

</div>

<div id="bar">

</div>

CSS

#foo,
#bar {
  height: 200px;
  width: 200px;
}

#foo {
  background-color: indianred;
  cursor: pointer;
}

#bar {
  visibility: hidden;
  background-color: steelblue;
}

#foo:hover + #bar {
  visibility: visible;
}