The HTML/CSS should be easy to pick up, but if you're having trouble following the Ruby code, I'd suggest you start with a Ruby off-Rails book. The Pickaxe book comes to mind. You can find the 1st edition online. Also the Ruby Way helped me to "get" the Ruby way of doing things.
Check out The Ruby Way and The Rails Way, they aren't tutorials but I think they will cover what you're looking for.
I'd start with Ruby-lang.org (including the tutorial in the link).
Beyond that, IMO another excellent activity to learn Ruby is the Ruby Koans, which help you learn idiomatic ruby through fixing failed unit tests.
Book-wise, for Rails I had good luck with Head First Rails. I'm currently chewing through The Ruby Way, which has been great for learning more idiomatic Ruby.
The HTML/CSS should be easy to pick up, but if you're having trouble following the Ruby code, I'd suggest you start with a Ruby off-Rails book. The Pickaxe book comes to mind. You can find the 1st edition online. Also the Ruby Way helped me to "get" the Ruby way of doing things.