I have finished reidang the whole book and it is the great book. Having said that, I have some suggestions.You put about css positioning. But the beginner might not be able to put them together. It would be better if you could add that one. I could not find (may be overlooked) about solving the cross-browser issues. Or browser based styling such as I think it is worth to explain <!DOCTYPE declaration and why it is used and how it could affect the CSS.