Now as a learning resource
This is a copy of the 2011 edition of the OPRF Tech website, but with lots of comments for beginners to see how the site was built.
Reading and Learning
The suggested method for using this resource for learning is to have an html file and the css flie open at the same time in two windows, with a web browser pointing to your html file. This way you can see how different pieces of the files affect each other.
It is suggested that you use Chrome or Safari while learning because of Webkit (the rendering engine)'s developer tools (Turn on Safari's developer tools). You can use the Developers Tool to play around with the site inside of the browser (the css sidebar is especially nice).
For new comers to website development, remember that you need to refresh your browser to see your changes (unless you're using the developer tools, in which case you need to transfer your changes from the tools to your files, otherwise the changes won't be saved).