might need to code that if there isn't a setting.
You're right in that you'll need to edit the CSS in the form editor. I had the same issue with one of my registration forms - the URLs below are a couple of discussion threads I started on how to add multiple columns to a checkboxes field type.
- Editing/ reformatting long list of values on a form
- Need Custom CSS to Alter Specific Form Field, not just the Field Type
Here's a thread on how to style radio buttons: Horizontal Radio Buttons