The "sign up" button on my Registration page is the wrong color.

I’m using Membership on my site and I’m having a couple of hiccups. One of them is an incorrect link color on the Registration form. The “SignUp” button is blue, which is fine, but for some reason the buttons on this page are borrowing my theme’s link color, which is also blue.

None of the other Membership form pages are having this issue; buttons on the Account and even Subscriptions pages are blue with white text.

How can I make the buttons on my Register page follow the default coloring?