clarkwinkelmann Child tags can have background colors. We made the choice to not give them any on this forum. That's something extra to take into account in the styling (background with tag color and border with parent color?)
Possibilities are endless, but I implicitly suggested in my prototype to remove the background in such a case, as I like the total opacity/total transparency contrast effect. But I agree this aspect should also be taken into account.
clarkwinkelmann Changing the text color could also hurt readability... But that's already an issue with background colors.
Indeed, bg/fg colors are an endless UI war... (On this particular subject, the ultimate solution would be to have an automatic fg color hue adjusting its contrast with the bg). But that's another story