Reduce Gravity Forms Submit button

Hi,

I've got a button on one of my pages which my Avada Theme must be styling. Is it possible vis some css code to just make the gravity forms button smaller? I already have some code to make it smaller on my booking page but its not working quite how I want it on the store products page I'm using with Appointments+.

Link is here

http://treatmeathome.com/store/products/jing-massage-90-mins-manchester-test/

See the "Show Available times" button. I want it more like the size of the "next month" button. I know I can use appointments and locations to do what I'm trying to do but it wont work for my website because appointments doesn't allow multiple locations for one service provider. I need a way around this problem.

Thanks
Kieran