Cannot change button color on hover

I’ve been using the tips in this thread: to try and adjust the color of my “Submit” button. The problem is, nothing I do changes the color on hover; it just overrides the transparent button color and leaves the hover color incorrect. I also haven’t been able to find the code in my theme’s footer sheet. Help? I want to make the button color the same as the rest of my theme’s main accent color, but for some reason it’s only showing up as the theme’s original accent color.

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