You need to add the [layoutResources|Tags] tag twice to your page, for the <head> resources and end-of-body resources.

Your grails-app/views/layouts/main.gsp:

{code:xml}
<html>
   <head>
      <g:layoutTitle/>
      <r:layoutResources/>
   </head>
   <body>
      <g:layoutBody/>
      <r:layoutResources/>
   </body>
</html>
{code}

