np 
.
Any specific reason why you wants to know the color?
As of now I don’t see any UiPath default activity for this but
there is a costume activity built by @andrzej.kniola which help Get colors from image (may be you can take screenshot of website and save it as image and then use this activity).
andrzej feel free to add if i’m missing something.
@ovi shall we move to idea category ? 