<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>
<p class="flex-containe">
<a role="button" href="#" data-toggle="modal" class="btn btn-lg btn-primary" data-target="#myModal" role="button">Launch Demo Modal</a>
</p>
<div class="modal fade" id="myModal" tabindex="-1" role="dialog" aria-labelledby="myModalLabel">
<div class="modal-dialog modal-smll" role="document">
<div class="modal-content">
<div class="modal-header bg-primary text-center">
<button type="button" class="close" data-dismiss="modal" aria-label="Close"><span aria-hidden="true">×</span></button>
<h2 class="modal-title" id="myModalLabel">Subscribe to our Newsletter.</h2>
<p>We promise we will not spam you.</p>
</div>
<div class="modal-body">
<div class="row">
<form action="#">
<div class="form-group col-md-12">
<div class="input-group">
<span class="input-group-addon">@</span>
<input type="email" class="form-control input-lg" placeholder="Your email here">
</div>
</div>
<div class="form-group col-md-12">
<input type="submit" class="btn btn-primary btn-lg btn-block" value="Subscribe">
</div>
</form>
</div>
</div>
</div>
</div>
