This was indeed the idea of the W3C when they wrote this. The page he links to even says that:
http://www.w3.org/TR/css3-mediaqueries/
"Among the media features that can be used in media queries are ‘width’, ‘height’, and ‘color’. By using media queries, presentations can be tailored to a specific range of output devices without changing the content itself."
The part "without changing the content itself" is pretty clearly not what he is doing here. Like dozens of others have said, just an interesting idea but not something that should be used like this in practice.
http://www.w3.org/TR/css3-mediaqueries/ "Among the media features that can be used in media queries are ‘width’, ‘height’, and ‘color’. By using media queries, presentations can be tailored to a specific range of output devices without changing the content itself."
The part "without changing the content itself" is pretty clearly not what he is doing here. Like dozens of others have said, just an interesting idea but not something that should be used like this in practice.