Top bar showing double color for Drupal Answers for both main site and meta site.
AFAIK the color for top bar is #212121 as mentioned in the blog. Check out the below screenshot. I can see this in opera and firefox on windows 7. It looks not nice on profile picture area.
With background set to be 100% transparent, it looks like this:
The dark blue ends abruptly, creating double-colour effect after adding black semitransparent overlay.