JSFiddle - React, Tailwind, and code Playground
HTML
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/css/bootstrap.min.css">
<span class="glyphicon glyphicon-plus"></span>
CSS
.glyphicon {
font-size: 120px;
}
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/css/bootstrap.min.css">
<span class="glyphicon glyphicon-plus"></span>
.glyphicon {
font-size: 120px;
}