JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="//cdnjs.cloudflare.com/ajax/libs/font-awesome/4.1.0/css/font-awesome.min.css">
<script src="//cdnjs.cloudflare.com/ajax/libs/font-awesome/4.1.0/fonts/FontAwesome.otf"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/font-awesome/4.1.0/fonts/fontawesome-webfont.eot"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/font-awesome/4.1.0/fonts/fontawesome-webfont.svg"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/font-awesome/4.1.0/fonts/fontawesome-webfont.ttf"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/font-awesome/4.1.0/fonts/fontawesome-webfont.woff"></script>
<span class="fa-stack fa-5x">
  <i class="fa fa-circle fa-stack-2x"></i>
  <i class="fa fa-flag fa-stack-1x fa-inverse"></i>
</span>

CSS

.fa-flag:hover {
    color: red;
}