Design Color

Hi there!
I am using the Owner theme, but would like to change the color of the active menu-items and the scroll-arrow… there are these three colors between one can choose, but I would like to use a different instead of orange blue or brown. I tried with style.css but it seems as if the information is stored somewhere else, too…?
Thanks for any advice or help!!
Cheers and keep up the good work!
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