I can get test to pass simply adding ‘background: red;’ where i have ‘black’. but trying it with black does not work (i don’t think fallback should be the same as existing declaration color anyway).
when i invalidate the variable color it is just white (blank), not black.
It won’t pass if you make the fallback black because the instructions tell you to use red.
There isn’t any reason why you wouldn’t want the fallback to be the same color. Usually you would want it to look as close to the same as possible.
My guess is that it’s equivalent to setting it to something like none, or unset. Different browsers handle this sort of thing slightly differently, but it’s not quite the situation that this challenge is preparing you for. This challenge will be more relevant at some point when you want to try out a new feature that isn’t implemented in all browsers, or one which is done slightly differently across browsers.