No, there is no need for a dedicated css meta tag. CSS is for styling a web page... in other words, for the design of Meta.SciFi. There is nothing the tag can be appropriately used for that is not also covered by design, whose description lists:
For questions regarding the design elements of the main and meta sites e.g. CSS issues
Emphasis mine.
The tag should therefore be synonymized with design in the long term (to prevent re-use), but in the short term, could probably be edited out by a 2k+ user from the whopping five questions it's on currently, and it will be deleted at the end of the UTC day.