Learn CSS Colors by Building a Set of Colored Markers - Step 2

Tell us what’s happening:
Describe your issue in detail here.

Your code so far
After correct code also its showing error

<!DOCTYPE html>
<html lang="en">
<head></head>
<body></body>
</html>

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/74.0.3729.108 Safari/537.36

Challenge: Learn CSS Colors by Building a Set of Colored Markers - Step 2

Link to the challenge:

Works fine to me, try reloding the site.