Learn CSS Variables by Building a City Skyline - Step 60

that’s my code so far
var(–building-color3) 7.5%,
var(–window-color3) 15%

but i don’t understand why the system keep telling me :

You should use --window-color3 at 15% for the third color.

I think you placed it under the wrong topic general instead of Html-css. At the challenge page, click ask for help and post the challenge here and the link to the challenge as well as the full code you have tried so far