app/views/layouts/panel.html.erb
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html>
<head>
<meta/>
<%= csrf_meta_tags %>
<title>Mercury Editor Panel</title>
<%= stylesheet_link_tag *Cmsimple.configuration.editor_stylesheets %>
</head>
<body>
<%= yield %>
</body>
</html>