I have looked at the tutorials (Building a Progressive Web Site) and also at the files, but I'm trying to figure out how the text will expand to each device to look approximately the same as well as images. I did not see any text size settings in the styles.css. Is there supposed to be and in what format, % or em? All the text is doing is re-wrapping when enlarging.
This tutorial is not comprehensive of all the topics needed for web design. Your idea about responsive text sizing is a great topic for a follow up tutorial so I've added it to the list of potential topics for us to cover.
In the meantime, I found this article which I found helpful for sizing text in responsive websites: And You Thought Responsive Text Was Just a Fad?.