We shouldn't use .tablet and .phone here, because a) they are not used anywhere else, but everything is done in the mobile.css, b) they are only available when JS is enabled, c) they are part of the template (because they are created in the template's script.js) and therefore shouldn't be used in any of the css files beginning with an underscore.

So, just `.mode_media div.page { overflow: auto; }` needs to be moved to mobile.css.