Styling mobile nav menu - colour decoration

Site URL: https://www.360sp.com.au/home1

Hi SS trust,

I'm trying to style my nav menu on a site, by adding a colour to the page last visited. I've managed to do it with code that is working fine on desktop, but mobile just won't work. 

https://www.360sp.com.au/home1

Code I've used is:

.header-nav-item--active a {
  color: #69BD45 !important;
  background-image: none !important;
}

.Mobile-overlay-nav-item:last-child{
   color: #69BD45 !important;    
  }

Any help would be hugely appreciated!

Thanks,
RAD.