How do I customize a Superfish Menu for Drupal 7? I have successfully installed Superfish by installing the Libraries module, downloading the Superfish library and putting it in /sites/all/libraries, and installing the Superfish module.

Now I would like to customize the look of it. The pre-built styles that show up in the drop-down in the Superfish Configuration could be a decent starting point, but I really would like to get into the details and get the measurements and colors just right.

How can I do this?
You need to overwrite the styles in your own custom stylesheet.  Use firebug to find which styles you would like to adjust.

Keeping it in your custom stylesheet will keep the styles from being lost when you update the module.