Styling based on parent pages

I have three main parent categories on my page and I would like to color code them, each with its own color. I tried looking for a plugin which would do this to no avail, then I tried checking how could it be done manually and I’m still not entirely sure. Any help would be most welcomed.
I would like to use something like checking for the ID of the parent page on the sub page and based on that including a specific stylesheet.