JSFiddle - React, Tailwind, and code Playground
HTML
<link rel="stylesheet" href="//netdna.bootstrapcdn.com/font-awesome/4.0.3/css/font-awesome.min.css">
<link rel="stylesheet" href="//netdna.bootstrapcdn.com/bootstrap/3.1.1/css/bootstrap.min.css">
<script src="//netdna.bootstrapcdn.com/bootstrap/3.1.1/js/bootstrap.min.js"></script>
<!DOCTYPE html>
<html>
<head>
<title>Font Awesome Icons</title>
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.min.css">
</head>
<body>
<div style="margin:20px">
<ul class="nav navbar-nav">
<li class="dropdown">
<a href="#" class="dropdown-toggle" data-toggle="dropdown">Dropdown <b class="caret"></b></a>
<ul class="dropdown-menu">
<li><a href="#"><i class="fa fa-square"></i> boh</a></li>
<li><a href="#"><i class="fa fa-square" style="font-size:24px;color:green"></i> Green</a></li>
<li><a href="#"><i class="fa fa-square" style="font-size:36px;color:blue"></i> Blu</a></li>
<li><a href="#"><i class="fa fa-square" style="font-size:48px;color:red"></i> Red</a></li>
</ul>
</li>
</ul>
</div>
</body></html>