Navbar Help in a purchased template

Hi all, I bought a Template and it uses two different background colors on its pages. Some pages have a dark background (and uses white text in the Navbar) and other pages have a light background (and use dark text in the Navbar). I have created a “symbol” with the Navbar with white text (to use on the pages with the dark background) but now need to create a “symbol” for the Navbar with the dark text to use on the pages with the light background).
My question is, can anyone help me know how to create, a “symbol” for a duplicate Navbar but with dark text (to use on the pages with the light background) but link the two Navbars together so that when I change something in either of them, the change is made in both Navbars? Thank you for any help and sorry if I’ve confused you with my description.