This demo uses two features of media queries:
If you look in the landscape.css CSS file, you'll see that media queries are used to change the font size of the body's text to make it larger the wider the window becomes, at specific window widths.
If you look in the head block in index.html, you'll see that media queries are also used to select two different style sheets -- portrait.css if the window is in portrait mode or landscape.css if it's in landscape mode. This moves the toolbar between the left and top edges, depending on which axis has the most available space.