For changing the categories menu style you should follow the steps below:
1. Download “skin/frontend/blank/themeXXX/css/styles.css” file to your computer and open it with your HTML editor
2. Once you are in your HTML editor, you may want to scroll down through the document to find the menu styles or use the search tool (CTRL+F). You should look for the navigation section.
3. In this section you can change the font style of the main menu buttons
4. When you are done, save the file and upload it to your server
5. That’s it!
