Theme and layout are disctinct.
You *can* do both in the same file for simplicity, but the default is to have a layout *and* a theme.
Look at the renaissance theme, it is just a CSS, it goes with the default layout which is a 2 column layout.
So you can already have a single theme and several layout to use on different pages.
Ok. Thats weird, because our "shipped" portal had just one css file with both theme and layout defined in it. What do I name the file containing the layout and where do I put it? Also how do I set a page to utilize this layout css file?
To choose your layout and theme using the management portlet (note that you can do it in the XML descriptors as well)
Here is the doc for packaging theme and layout.
If you look at the sources of the portal you got you will find the layout defined here:
and the default theme here:
thanks a bunch!