JSFiddle - React, Tailwind, and code Playground

HTML

<div class="cs-menu">
			<div class="item">one</div>
			<div class="item">two</div>
			<div class="item">three</div>
</div>

CSS

.cs-menu {
	position: fixed;
	top: 35%;
	right:10%;
}

.cs-menu .item {
	border: 1px solid red;
	width: 40px;
	height: 40px;
	background: #f9f397;
  transition: width 1s;
  float: right;
  clear: right; 
}

.cs-menu .item:hover {
  width: 150px;
}