As you can see it is preceded by penguin class with a color declaration for the penguin-skin variable,. I still get the following error message:
The penguin-skin variable should be applied to the background property of the
penguin-top class.
Can you edit your post for readability. When you enter a code block into a forum post, please precede it with a separate line of three backticks and follow it with a separate line of three backticks to make it easier to read.