Button active state Image Overlay Bric

Hello Blocs Crew,
I really like the Overlay Image Bric,
so far I was able to style many things.
I even managed to style the button in the image overlay by choosing via inspector and creating the class “overlay-btn”
I could change it to outline, white everything I wanted except for the active state. It will be ALWAYS a whitish tone with transition when clicking the button.
I tried also to use the class “btn-light” which somehow has the same effect on the button of the image overlay. All my other buttons have no active state. How can I achieve it?
I am happy for some hints and tips of you.
Thank you in advance.