Suggestion: Fixing Css alerts in Firefox

As a developer, I think it will be cleaner if the CSS errors that appear in the Javascript Console (Firefox) are somehow fixed it will be really cool.  The errors are always the same:
Error: Expected identifier for class selector but found ‘{’.  Ruleset ignored due to bad selector.
Source File: quirksmode.org/css/condcom.html
Best regards,
MARTIN

Thanks for reported problems - we will try to fix them where possible, but in any case it will not be ideal.

>>But maybe there is a nice way to avoid them like:

Yes, it can be done in such way, but in such case this style need to be manually added to any document where grid placed - this is not a good solution on my opinion.