Tweak nav submenu heading color

netbox/project-static/styles/variables.scss

@@ -24,7 +24,7 @@
   --nbx-sidenav-link-color: #{$gray-800};
   --nbx-sidenav-pin-color: #{$orange};
   --nbx-sidenav-parent-color: #{$gray-900};
-  --nbx-sidenav-group-color: #{$secondary};
+  --nbx-sidenav-group-color: #{$gray-800};
 
   &[data-netbox-color-mode='dark'] {
     // Dark Mode Variables.