Yesterday, someone asked #wikipedia where was the separation between style and content done on wikipedia. Users don't suddenly start to write CSS rules in the pages themselves. Most inline styles come from templates.
They don't write for a table: border="2" cellpadding="4" cellspacing="0" style="margin: 0.5em 0.5em 0.5em 1em; padding: 0.5em; background: #f9f9f9; border: 1px #aaa solid; border-collapse: collapse; font-size: 95%; but do {{tabla bonita}}
Similarly, the infoboxes CSS don't come from the article content, but from a template two or three layers down.
Fixing 80-90% of the inline styles should be quite simple, as it'll come from a few templates. The problem is to detect *when* that style gives problems on mobile.
I'm not sure what we are trying to mean with it, "it doesn't look right" isn't simple for an algorithm to detect ;) If we need to manually view the page, we could hardly detect it.
OTOH if we are looking for absolute values in that inline, it's simple to do.
So what constructs are problematic for mobile? How to detect them?
Once we have such measures, it shouldn't be hard to go fixing it. Moving css rules from inline styles to site CSS can be a step for fixing the problems (and also recommendable for other reasons), but is not the solution.