I appreciate what you are saying about the secondary and tertiary colours - but (with respect) - I think you are still missing the point as these colours don't have anything to do with the Nav suggestion?
Having just 4 colours seems very limiting. Having to rely on a plugin or custom coding to go further does again appear to miss an opportunity to do something more flexible.
Here's one suggestion. (you need to use the 'Orange' menu colour as this overwrites it.)
Call it User HSL Nav.
5 parameters all based on @pl-base (site background colour - although that could just as easily be a user value)
Note: Just a quick experiment. As long as your background colour is not grey (it has a tiny amount of colour) this will pick up the background colour and produce a nav bar the same colour - or if you enter 0-360 in the spin parameter, it will colour the nav bar with an offset colour from the background ie 180 will give you a nav bar the complimentary colour to your background.
Sat shift: plus or minus % from the background saturation
Grad top and base controls the lightness of the gradient.
@spin_amount: 0;
@sat_shift: 20%;
@rule_darken_amount: 20%;
@grad_top_lightness: 60%;
@grad_base_lightness: 20%;
.navbar.pl-color-orange
{
#gradient > .vertical(
hsl(hue(spin(@pl-base,@spin_amount)), saturation(@pl-base)+@sat_shift, @grad_top_lightness),
hsl(hue(spin(@pl-base,@spin_amount)), saturation(@pl-base)+@sat_shift, @grad_base_lightness)
);
border-top: 1px solid darken(hsl(hue(spin(@pl-base,@spin_amount)), saturation(@pl-base)+@sat_shift, @grad_top_lightness),@rule_darken_amount);
.searchform .searchfield
{
border: 1px solid darken(hsl(hue(spin(@pl-base,@spin_amount)), saturation(@pl-base)+@sat_shift, @grad_top_lightness),@rule_darken_amount);
}
}
A user hex value nav would also be welcome.