Dynamic underline of a header item as i scroll down within the home page

Hi there,

i have a site with just a home page and then link pages that appear in my navigation. (attached screenshot).

I would like for the header to be underlined as i scroll down to different sections on my page.

ie if i scroll down to the Location section, then i would like the Header "Locations" to be automatically underlined.

would really appreciate ANY help on this one please.

Much appreciated!