Would it be useful to come up with a dynamic mobile styling feature based on the lighting of the users environment. Similar to how the imac reduces its brightness if you cover the cam on top of the screen.
This is useful because mobile devices are used in environments of different lighting. while dark gray text on a light grey background will look pleasing on the eye indoors. this wont be the case when the user uses the phone outdoors, which in case a more contrasting style like black text on white background might be better.
http://babich.biz/mobile-ux-great-typography-enables-clear-communication/