Style toggle button via css class

I want to style the toggle button (the one opening the content of the toggle card), specifically increase the stroke-width. When I code inject that to it’s class (cls-1), that doesn’t work, it only works if I add ‘style=“stroke-width: 5;”’ to the . Why? what am I missing?

Are able to share a link to a page where this is happening? It’s difficult to say without seeing it firsthand.