<meta http-equiv="Content-Style-Type" content="text/css">
You only need this if you use the style attribute - and you are usually best off avoiding that in favour of real stylesheets.
W3Schools is unfortunately popular. It seems to get a lot of traffic by trading off the closeness of its name to that of the W3C and a significant number of people are surprised to find that they aren't the same organisation.
Sadly, it is more than a little error prone and its examples have a tendency to run as far away from best practice as possible.
The specifications at the W3C are good, and Opera has a good set of tutorials. I would suggest using these instead.