Sure the spec might be enormous but you don't need to touch it at all to be productive quickly. In no HTML or CSS tutorial i'v ever seen was a reference to the spec nor did i need to go there to solve something. And that in itself is another proof how nicely it is designed actually. Because on the other hand there are other document types or schemas where you absolutely have to go to the spec because it's is so cryptic and badly designed and not self-explaining that there is nothing else you can do.