detect JS with CI?

[eluser]xwero[/eluser]
I think the best thing you can do is to set one screen resolution as the default and load the other css with rel="altenate". When javascript finds the viewport size it can decide if the default style stays or if the style needs to be changed. this way you always have a styled site.

About the graphics. For a menu it's best the graphics are only background images for accessibility reasons. So you will always have text to fall back on for the site navigation.