If you are on a local server, you will need to get Firefox and its Web Developer extension and find the culprit yourself. The Information > Display Element Info will show you all id's/classes etc. asociated with an element, and then you can style the appropriate one in your stylesheet.

I'm not exactly sure how to use this tool yet. It's only local so far (for ease of development) and I'm not sure what to do to "find the culprit".