By default, all the .panel does is apply some basic border and padding to contain some content.
<!DOCTYPE HTML>
<html>
<head>
<link href="http://java2s.com/style/bootstrap.min.css" rel="stylesheet">
<!--from ww w .j a v a2 s. c o m-->
<script src="http://java2s.com/style/jquery-1.8.0.min.js"></script>
<script src="http://java2s.com/style/bootstrap.min.js"></script>
</head>
<body style='margin:20px;'>
<div class="panel">
Basic panel example
</div>
</body>
</html>