Talking personally, I published my first website in 1994 when there wasn't different layout modes. Now it is suggested that I read a multi-chapter book just to learn what's changed in CSS so I can publish the same content I had before but in a "web 3.0" (for want a better description) format.
I appreciate my comments are very ranty / preachy and do value your comment as I hadn't seen that link before; so my comments are not directed at you in any negative way at all! What I'm essentially just trying to say is web development has become very frustrating for anyone outside of the webdev community. Heck, I find it frustrating and I used to specialise in hardening web servers so have worked quite close to that community.
It's just that what people want has gotten a lot harder to build.
I should add that I don't disagree with the deprecation of <center> from a language purists perspective. However it was still a step backwards in terms of ease of development when centring stuff in CSS is so clunky in comparison.
http://book.mixu.net/css/
can help with the trial and error bit. It impossible to get an intuitive feel for nearly 400 keywords IMHO.