Hey, I have your book! "The Pragmatic Programmers: HTML5 and CSS3" right? :)

You were lucky because you consistently had the entire page width. For mine, because the book's formatting was pre-defined, the column width was variable depending on content type. I could have anywhere between 20 to 65 chars for code. The only place I had control was in the screenshots of code in Vim, but even Production decided to scale those down to make it fit.