Yeah, you can't zoom this page on desktop browsers. Although you can in mobile Safari. Chrome and Firefox seem to simply scale the underlying the pixel value in order to achieve page zoom, whereas mobile Safari seems to zoom into the viewport which, paradoxically, leaves part of the viewport unviewable.
However, desktop zooming should trigger any media query switches you've put on the page.
However, desktop zooming should trigger any media query switches you've put on the page.