<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>
<div class="container-fluid">
<div class="row-fluid" >
<div class="col-md-offset-4 col-md-4" id="box">
<h2>Login</h2>
<hr>
<form class="form-horizontal" action=" " method="" id="contact_form">
<fieldset>
<div class="form-group">
<div class="col-md-12">
<div class="input-group">
<span class="input-group-addon"><i class="glyphicon glyphicon-user"></i></span>
<input name="first_name" placeholder="Username" class="form-control" type="text">
</div>
</div>
</div>
<div class="form-group">