Finding “Add to cart” buttons via “Inspect” (Envo)

Hi. I am trying to change color, etc. on my website. I used the “Inspect” tool and found what I thought were the correct classes to do so. I placed the following code in my “Additional CSS” section:

.a .button .product_type_simple .add_to_cart_button .ajax_add_to_cart {background-color:green}

.a .button .product_type_variable .add_to_cart_button {background-color:green}

I also tried a number of other combinations of terms to see if I could make it work, but to no avail. Would someone be able to show me what I have done wrong?

The page I need help with: [log in to see the link]