Help with styling signup pages

@Jude Could you give me pointers on styling the below:

Align the Stripe button found here:

http://thesbcollective.com/experience/register/?action=register_user&step=payment_table&membership_id=59

with the login button found here:
http://thesbcollective.com/experience/login

I would also like to remove the green note above this form but leave the note when a coupon is applied. I don't see any shortcodes avilable to edit on the register page in WP so I'm quite confused. I also want to align the text to the center and give them some better spacing as it all looks quite bunched up.

Thanks,

Ash