Absolutely. All the css files that determine the look of your site are exposed to you in the admin panel. However, customizing your css is NOT supported in your standard product support. As a result, customizing your css files is recommended only for advanced users.
To customize your css files:
- Select Website in the left menu
- After you've determined advanced/basic mode, select the Site Configuration tab
- Go to the Advanced tab
- You will now see the basic css components that are easy to modify for all users.
- Click the Advanced link in the bar at right. This will take you to a page that exposes all of your css files.
- Make edits as you wish. Refresh your website to see the changes.