Styling plugins should be approached the following way.
1- Make sure you explore ALL the plugin options AND READ the plugin help to see if it offers a way to directly style or use custom CSS to do so.
2- If not finding what you want, contact the plugin developer to see what he has to say about your request (either provide a solution or consider adding the feature).
3- If none of the above are successful, inspect your page with your browser developer tools (http://forum.weavertheme.com/discussion/1207/basic-tips-on-using-the-developer-tools-like-firebug-to-resolve-styling-issues ) to see what rules are being used to style the property you want to change.
Once you know which rule does the job, add that same rule with your own values to The theme Custom CSS Rule box (Main Options > Fonts & Custom > Custom CSS Rule Box) to override it. You may need to add !important to your CSS properties if it does not work.
4- If having a hard time doing 3, provide a link to your page with specific details about which objects you are trying to change and how.