what @brandon_wallace is saying is a fallback in case the variable has not a valid value
you need a fallback for browsers that don’t know about variables. So, think, how would you declare background color if you didn’t know about variables? you just need to add that in the empty line above the existing background rule
that’s a fallback in case the variable doesn’t point to a valid value
this challenge is asking for a browser fallback, in case the browser can’t read variables at all, and in this case adding a fallback inside the variable is useless because it is not valid code for those browsers