Hello this one is a minor but conceptual change, on the hsl lesson you have Saturation defined as:
Saturation is the amount of gray in a color. A fully saturated color has no gray in it, and a minimally saturated color is almost completely gray. This is given as a percentage with 100% being fully saturated.
However saturation (in the additive model used for screens) refers to the presence of the hue on a mix, a full saturated “color” has 100% hue and comes as pure while a 0% saturated mix has no pigment/hue and that’s why it is rendered as grey on a value scale (in this case the Lightness property remains constant).
It is possible to lower a mix’s saturation (on a substractive model used on traditional painting) by adding grey but it is also possible to do it by adding it’s complementary color or white or black or water (in case of watercolors) but given that it is a web focused course this model shouldn’t be taken as the norm in my opinion.
So far the course is great and it is also one of the few that offers insight on elements of graphic/web design along coding which is awesome, thank you so much!