that would still call a variable called red-color
the issue is that the tests are checking that you did not change anything, and are checking what’s written in the editor
there are not many ways to check how a css rule is created
I respectfully disagree with that. background: var(--red-color,); would not still call the variable red-color as there is a name mismatch. You can see this by commenting out background:red; in the code above. Once you do that you would see that there is no longer a color which means it’s not calling the variable.
The only thing the original poster changed was adding background:red; and a comma between the “r” in color and the closing parenthesis.