<link href="//maxcdn.bootstrapcdn.com/bootstrap/3.3.0/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//maxcdn.bootstrapcdn.com/bootstrap/3.3.0/js/bootstrap.min.js"></script>
<script src="//code.jquery.com/jquery-1.11.1.min.js"></script>
<link href="https://fonts.googleapis.com/css?family=Hind" rel="stylesheet">
<link href="https://fonts.googleapis.com/css?family=Lato" rel="stylesheet">
<div style="margin:5% auto">
<div class="col-md-8 col-md-offset-2">
<button class="btn btn-primary btn-xs"> Refresh </button>
<button class="btn btn-primary btn-sm"> Refresh </button>
<button class="btn btn-primary btn-md"> Refresh </button>
<button class="btn btn-primary btn-lg"> Refresh </button>
<button class="btn btn-primary btn-lg" id="btn"> Refresh </button>
</div>
</div>
