HI Josh,
As of right now, you do have to add your custom CSS to each form you created, unless you are cloning from a form that already has the CSS in it. Another way you could do it, as you mentioned above, is to add it at the template level. If you go that route, then I would suggest styling all the different types of form elements, that way you wouldn't have to go back and add styling for different types of form fields used on various forms.