[NSFW] Fix size of checkout fields

As you’ll see from the above link, on my checkout page under ‘Additional Information’ the ‘Order Notes (optional)’ field is strangely small. Scrolling down the page you’ll also see that the ‘Where did you hear about this course’ field also has a tiny box to write in rather than it being the same size as the fields above. How do I adjust the size of these fields and make the whole page more uniform?

I am using the Coaching theme from Thimpress.

The page I need help with: [log in to see the link]