I don’t know. I can’t replicate the issue so I can’t provide you with a solution.
If you use Internet Explorer, Chrome, Firefox, Safari or Opera you can use the browser’s built-in developer tools to point at and “inspect” elements on a web page to find out what styles they use. You can even tweak the styles live to experiment with any changes you might fancy.
If you can post a link to a live web page of yours that displays the issue I will be glad to take a look.