I know the answer to this varies by browser and platform, but for someone with an Android phone I want to know if there's any way I can test and use my own stylesheets for a mobile site that you do not own (like loading user stylesheets with special rules in Firefox).
The site in question is a message board and it has its own "mobile" version but frankly, it's a terrible execution for a mobile site. Text is too small, partly because there are several columns of data that aren't necessary for browsing the boards, it has many thick, dark borders, etc. I want to clean up the layout by hiding some things and re-arranging others. I haven't styled a website for a mobile platform before, and think it would be a fun exercise if I can do this.
You would do that with a media query detecting the view port dimensions that match the android phone. Though the ideal way to approach mobile devices is outlined here. Though IE6,7 and 8 do not support media queries you can can get around that by using IE conditional comments to apply the desktop styles in those browsers.
Developers have full access to the same framework APIs used by the core applications. The application architecture is designed to simplify the reuse of components; any application can publish its capabilities and any other application may then make use of those capabilities (subject to security constraints enforced by the framework). This same mechanism allows components to be replaced by the user.
Are media queries simple to do from a beginner's point of view (beginner to mobile website development)? They seem simple enough if you are already intermediate in CSS. I don't have a problem not supporting IE browsers since I use Google's Android browser and Opera. This custom stylesheet is just to solve a personal problem.