How can I change the color of the buy button on mobile version?

[Nötter]

Hi everyone, I'm trying to change the color of the buy button and it doesn't work, because in the mobile version the color is white and I've tried the methods that are included in the chat. Can anyone help with that? I have looked at other solutions and tried copying and pasting code, but that never seems to change anything in my page. Instead of white, I would like the color to be same us computer.