The challenge asks you to add a background declaration that doesn’t use variables above the current one so that a browser that can’t interpret that line will have a rule above that to use, the last code you posted seems just the starting code
Reset your code, and focus just on the background rule
The one present uses the variable declared above. And that is awesome, you can use that variable to make various things in the web page the same colour, and then change only in one place to try different shades.
But we need to think also about old browsers. So we need a background property with just value of red so that if they can’t render the rule with variable will look above it for a rule they can use
The name of the property is the same, you need to give it a different value than the already existing one