JSFiddle - React, Tailwind, and code Playground

HTML

<div class="menu">

  <div class="innerMenu"></div>
  
  <div class="innerMenu"> </div>

</div>

CSS

.menu {
  width: 150px;
  height: 200px;
  border: thin solid red;
  //display: block;
}

.innerMenu {
  //width: 100%; 
  border: thin solid green;
  //min-height: 10px;
}


div.menu:hover {
  width: 300px;
  transition: 2s;
}


div.innerMenu:hover {
  height: 60px;
  transition: height 2s;
  -webkit-transition: height 2s;
  -moz-transition: height 2s;
  -o-transition: height 2s;
  -ms-transition: height 2s;
}