I am confused about an error in code

I just began the freeCodeCamp. I have reached the lesson: Basic CSS: Use RGB to Mix Colors.
When I run the test it says there is an error in the code.
I have retried entering the code and I have watched the video and I am still unclear as to what I am doing wrong. I have attached a screenshot showing the issue.

Any help would be greatly appreciated

Please post the link to the challenge and your code as text wrapped by three backticks (```).

Next time, you can also click the “Ask for Help” button in the challenge window and “Create a help post on the forum”, this will include the information we need to help you.

Make sure you end each CSS declaration with a semicolon, the tests fail if you don’t.

Just for future reference, technically you can leave semicolons off if the declaration is the last one in a block — eg

.my- class {
  height: 10px;
  width: 20px

That’s fine.

.my- class {
  height: 10px
  width: 20px

This isn’t, it won’t work. Some CSS properties take a list of stuff separated by spaces (border: 10px solid black;). If you remove the new lines from the above it’s easier to see why:

  height: 10px width 20px

The CSS parser is going to think it’s a property height with 3 parameters. And that’s not a thing, so it won’t work. The semicolons separate everything out, like full stops do for sentences.

Because it’s really easy to mess up (for example, you add another property after the last one, and forget to put a semicolon after that one), best practice is semicolons after each one.

Thank you
I will redo the exercise again and post from the challenge

Thank you for the useful tip.