2.1.2 [CSS-Level2-2009] Section 4.1.5, At-rules

V0003:

The specification states:

 CSS 2.1 user agents must ignore any '@import' rule that occurs inside a block or 
 after any non-ignored statement other than an @charset or an @import rule.

Quirks Mode (All Versions)

The @import rule is not ignored if it follows any valid statement except @charset.

Quirks Mode and IE7 Mode (All Versions)

The @import rule is not ignored if it is contained within a block.

IE7 Mode (All Versions)

The @import rule is ignored after a bad selector, when it should be parsed and executed.

V0179:

The specification states:

 At-rules start with an at-keyword, an '@' character followed immediately by an 
 identifier (for example, '@import', '@page'). 

Quirks Mode and IE7 Mode (All Versions)

At-rules that start with the at character (@) followed immediately by spaces, tabs, numbers, dashes, or other special characters are ignored and do not allow the actual keyword command to be executed.