Although, I have also noticed that not every attributes described on CSS2 spec, section 15 (Fonts) are implemented. For example, none of the attributes on section 15.3.6 ('panose-1', 'stemv', 'stemh', 'slope', 'cap-height', 'x-height', 'ascent', and 'descent') seem to be implemented. What should I do? Should I implement them in SPStyle? Or should I implement it on SPFontFace ?
Interesting question. Off hand it seems to me that you should put it in SPStyle if it is CSS information, but Richard could probably comment on that better.
Actually I can't comment any better - that's almost exactly what I would have said.
The amount of memory occupied by SPStyle does occasionally concern me - particularly for the text properties, which are numerous and infrequently used (consider one of ScislaC's specials, for example, where every strand of hair has a font-family). I don't know of anybody who's thought of a better way of doing it, though.
Richard.