Now that Yahoo! is rendering (most) media queries I found that modules designated to show on mobile devices via a class similar to the following render blank, while media queries to hide/scale content appear to function properly:

.showForMobile {display: block !important;
width: 320px !important;
/* height: 100% !important; interferes on Safari with scaling, however is needed for Firefox */
height: auto !important;
overflow: visible !important;
position: static !important;
min-height: 100% !important;
max-height: inherit !important;
line-height: normal !important;
font-size: medium !important;}

For example, I have 2 navigation menues—one for desktop and one for mobile that link to completely different pages. Neither display in the Yahoo! Mail app as the desktop menu is set to hide for mobile (which it does) and the mobile menu is set to display (but it doesn't). Can anyone advise on a solution?

Thank you.