Div styles not showing up on mobiletablet versions

I'm using the theme Modelling (http://smthemes.com/demo/modelling/) and am having difficulty getting styles for the "secondarymenu", "mainmenu", and "content" divs to show up on mobile/tablet versions of the site.

I followed the tutorial here (http://smthemes.com/support/topic/howtodisablemobileandtabletmodes/) to disable mobile/tablet versions of the site but my styles for "secondarymenu", "mainmenu", and "content" still do not appear when I load the site on an iPhone/iPad.

I've also reverted to the original, untouched version of the theme but, upon loading it onto my iPhone & iPad, I still experience the same problem. The dark grey background is the only bgcolour visible through the secondarymenu, mainmenu, and content divs.

Any help would be greatly, greatly appreciated!

Thank-you!