I'm mainly Sysadmin, got some html and css knowldge, but not super deep, I'm really interested on building apps based on web taking the html5 and css 3 advantage, of course I'm already learning javascript (know Perl), but after looking for some books to get in html5 and css3 it seems that all of them assume you have a deep knowledge of xhtml and css2.

What should I do? what should I learn? any good book or path you would recommend me?

Many thanks.