Theme customizing documentation improvement.
I'm studying themes, and existing themes are simple to use, but looks complex to make. The Vaadin book has a big chapter on CSS and a very small page on Vaadin themes.
The Theme sample application shows how to use existing theme.
I found no big enough example or tutorial on how to customize an existing theme (other than change the body background color).
Example of more complex things that would be worth documenting: how to change the appearance of buttons (by only providing new bitmaps if possible).
I'd like to understand existing theme betters without having to understand them too much. I don't know what part of the theme to study, like if I had no hook point. A tutorial would help. And would probably help the community to create other themes. Probably not full themes, but themes inheriting reindeer.
A dictionary of all the possible property/value combinations for all Vaadin Gui objects will be really handy.