Getting rid of border around linked form buttons!

Hi, I installed a donate now button on my donate page, and there’s an orange border around the form input field and the donate button.

I’ve tried going through the css stylesheet to find where to change that, but I haven’t had success yet.

How do I change this so no border shows up?

Also, I want to get rid of the plain black borders around images, on other pages, if possible.

Thanks!