You can use themes and variants in whatever way you choose, but the general idea is that you can use different themes for different publications that you want to have completely different appearances, and use variants on those themes for minor variations within publications at the section level (so that the Sports section looks different from the News section, for example).
The Widget Framework is supplied with one theme called
default, which has an empty variant called
variant. It is possible to make themes and variants of
skills). This manual does not, however, cover the design and creation of
custom themes and variants.
Themes and variants can be set on a per-section basis, allowing you to give a different look-and-feel to different parts of a publication. For a description of how to do this, see Changing Themes and Variants.