Are there any accessibility guidelines to compare background color of a button with background color of a page?

Question

Color of my button:#73c998 Background color of my page: #2C6C9E

While this tool below tests the colors as if one of them was a text color, do we have anything for background to background comparison?

See link: http://leaverou.github.io/contrast-ratio/#%09%2373c998-on-%232C6C9E