Dialogflow CX - Different colors on buttons

Hello,

I have two buttons in my payload and want them to have different colors, does anyone know if it is possible by using the provided CSS variables?
Dialogflow Messenger fulfillment | Dialogflow CX | Google Cloud

This is my goal:

I do not think that is possible, I saw you can modify the Icon color and the hover colors in other buttons like chips but not the color itself of the button.

What I saw is that you can change the primary color only globally: https://cloud.google.com/dialogflow/cx/docs/concept/integration/dialogflow-messenger/css