It worked fine on a 6" device on Firefox for Android for me, however the text was small, and when zooming it only shows the zoomed slides in the original viewpo

It worked fine on a 6" device on Firefox for Android for me, however the text was small, and when zooming it only shows the zoomed slides in the original viewpoint which doesn't change. I tested on an iPhone 5S which has a much smaller screen, so I need to zoom, but when zooming the page ends up messed up.