Hello,
This bug is a CSS2 parsing error, and has a little relation to CSS3 media-queries.

An @media rule specifies the target media types (separated by commas) of a set of statements (delimited by curly braces). Invalid statements must be ignored.
http://www.w3.org/TR/CSS21/media.html#at-media-rule

@media statement1, statement2, statement3 { ... }

Currently the CSS validator will wrongly discard the whole @media rule if one of the statements is invalid, for instance a statement like "this is an error" containing multiple spaces (side note: this is used by CSS3).

== Example ==

@media handheld, only screen and (color)
{
	body
	{
		color:blue;
	}
}

We know that the statement "only screen and (color)" is invalid in CSS2 and should be discarded, but the other statement "handheld" is valid in CSS2 and should be kept.

The CSS Validator returns:

1	unrecognized media only
1	Parse Error screen and (color) { body { color:blue; } } 
@media handheld

The modified CSS stylesheet returned by the validator is invalid, and does not contain the body of @media handheld { ... }

Please note that the example is taken from CSS3 to be relevant, but as far as CSS2 is concerned, it should work just like "@media handheld, some invalid statement, another invalid statement { ... }".

== See also ==

CSS3 media-queries:
http://www.w3.org/TR/css3-mediaqueries/#error-handling

Best regards,
Alexandre
http://alexandre.alapetite.fr