You would also style the form using CSS just like you would style anything else on your site. View the source, see the classes and id's that are used, and write CSS to target those classes and/or id's. You would place this CSS in your themes stylesheet.
Here is some documentation on the CSS elements that Gravity Forms uses.
CSS Style Guide:
How to target form elements:
Posted 8 years ago on Sunday January 16, 2011 | Permalink