JSFiddle - React, Tailwind, and code Playground

HTML

<div id="div">привет</div>
<p id="poka">пока</p>
<p>адью</p>

CSS

#div, p {background:#b3b3b3;margin:5px;}

#poka{opacity:0;display:block;
-webkit-transition:opaity 1s;
  -o-transition:opaity 1s;
transition:opaity 1s;
}

#div:hover #poka{opacity:1;}