Problem

Answer code is not matched (typo) with instruction on Basic CSS: Attach a Fallback value to a CSS Variable

How to reproduce

Try to answer with background: var(--penguin-skin, black); on both penguin-top and penguin-bottom. It will tell you that the answers are wrong. But, when you change the answer line to background: var(--pengiun-skin, black); The answers would be right.

Accepted answer is --pengiun-skin.
It should be --penguin-skin.
It's pengUIn, not pengIUn
It refers to variable --penguin-skin on class penguin.

The link

https://learn.freecodecamp.org/responsive-web-design/basic-css/attach-a-fallback-value-to-a-css-variable/

Browser and operating system

• Browser Name: Firefox Quantum
• Browser Version: 61.0b5 (64-bit)
• Operating System: Ubuntu 16.04.4 LTS

Screenshot