Underline interaction navigation

Hi Webflowers,

I’ve created this underline interaction in the navigation of this site:


But having problems getting my head around setting elements/classes so that this interaction repeats across any ‘nav-link_div’ that I add. Please note these are different colours for different sections of the site, so therefore I’ve combo classed these ‘first’ and ‘second’ here.

Please feel free to advice on wider best practice here.

Greatly appreciated.


Here is my public share link: LINK
(how to access public share link)