Does Marketo have a full overview of form CSS classes?

From time to time we update the look and feel of our Marketo Forms. This requires a lot of effort, because we don't have a clear overview of CSS classes. Often this results in unexpected behavior.

I've searched for an overview in the documentation, but can't find any documentation on CSS at all. Does Marketo provide an official documentation of available CSS classes? Or is there someone who has created something like this that he/she can share? It would make our work a lot easier.