CSS styling radio buttons, running out of ideas.

I'm creating a form for a donation page. I want to have it so that you can only choose 1 option (options are $5, $10, etc.) So I think I need to use radio buttons.

Problem is they are ugly. I want a button that's a rectangle with rounded edges and you can click anywhere on it. When clicked, the background color and text color would flip, indicating it's been clicked.

I can do this with regular buttons, but have no idea how to do it with radio buttons.

Any help?