I had stopped XOOPS Cube Core development and next BASE development for a long time. Today I restarted it for the first time in many months. But, I did not modify most core code, because my first priority task is theme rendering for another developer who tries to define one of next generation themes.
As you know, XOOPS Cube doesn't force a theme format. Therefore, a theme at this entry is not "uniformed new next generation theme", but one of next generation themes. Programmers have to test the feasibility of exchangable theme format.
This theme format written by Mr. jidaikobo has "style" spec. The style is similar into RapidWeaver's "style". See the following screen shot. It is the same look as XOOPS Cube Official Site BETA that is generated by RapidWeaver.
Changes style to change look. That is switching CSS.
Most next generation theme formats are probably not table-based layout. So it will become tough work to create themes. "Style" makes it possible to change looks by switching CSS on the same template.
Jidaikobo has some ideas for CSS-based theme format. He proposed a new way that themes don't have any templates. Instead of templates, the themes have only CSS files and image files. In other words, the themes perhaps equals the style that I've just tested. That's difficult, so there are some discussions.
BTW, code on my PC is very bad. Please wait for my commit.