[prs]

Beautiful implementation.

As stated elsewhere in the thread, it is work in progress, so do not be too harsh of a critic.

Once all the lessons are up and a responsive layout is implemented, I believe this to be a beautiful addition for beginners and advanced programmers.

P.S.: Reminds me a bit of http://www.phptherightway.com - Maybe you can borrow a few of the good ideas from that guide?