<!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>
<h3><strong>Stacked icons:</strong></h3>
<span class="fa-stack">
<i class="fa fa-circle-thin fa-stack-2x"></i>
<i class="fa fa-twitter fa-stack-1x"></i>
</span>
fa-twitter on fa-circle-thin<br>
<span class="fa-stack">
<i class="fa fa-circle fa-stack-2x"></i>
<i class="fa fa-twitter fa-stack-1x fa-inverse"></i>
</span>
fa-twitter (inverse) on fa-circle<br>
<span class="fa-stack">
<i class="fa fa-camera fa-stack-1x"></i>
<i class="fa fa-ban fa-stack-2x text-danger" style="color:red;"></i>
</span>
fa-ban on fa-camera
<h3>Use of large icon class on parent element (fa-lg):</h3>
<span class="fa-stack fa-lg">
<i class="fa fa-circle-thin fa-stack-2x"></i>
<i class="fa fa-twitter fa-stack-1x"></i>
</span>
fa-twitter on fa-circle-thin<br>
<span class="fa-stack fa-lg">
<i class="fa fa-circle fa-stack-2x"></i>
<i class="fa fa-twitter fa-stack-1x fa-inverse"></i>
</span>
fa-twitter (inverse) on fa-circle<br>
<span class="fa-stack fa-lg">
<i class="fa fa-camera fa-stack-1x"></i>
<i class="fa fa-ban fa-stack-2x text-danger" style="color:red;"></i>
</span>
fa-ban on fa-camera