Several "add to cart" buttons with different colors for each one.

Site URL: https://www.focusnutritionus.com/

I'm building a website for a client and this is absolutely insane. I cannot for the life of me find out how to change individual "add to cart" buttons colors. I have three product blocks with add to cart buttons that need to be on the same section for some plans the website is advertising. I cannot find the code or keywords to change only a single product's add to cart button color, which does not seem like a reasonable limitation from the web builder. I've tried using the block ID for the specific product but it completely breaks the buttons design instead, as if it doesn't follow the same CSS rules as any other block. 

To specify, I want them to all be different colors for "START PROGRAM NOW" or "SIGN UP NOW" - the button on the far right is just that, a regular button. The button in the middle is the button I have applied site-wide CSS to but it changes ALL Add to Cart buttons to that style. 

Worked perfectly! Thankyou very much for the help, @creedon. It is very much appreciated 😄