2.1.3 [CSS-Level2-2009] Section 4.1.6, Blocks

V0180:

The specification states:

 A block starts with a left curly brace ({) and ends with the matching right curly 
 brace (}). In between there may be any tokens, except that parentheses (( )), 
 brackets ([ ]), and braces ({ }) must always occur in matching pairs and may be 
 nested. Single (') and double quotes (") must also occur in matching pairs, and 
 characters between them are parsed as a string. See Tokenization above for the 
 definition of a string.

Quirks Mode and IE7 Mode (All Versions)

The following variations apply:

  • Nested blocks and strings are not parsed correctly.

  • Blocks and strings with terminating pairs that do not exist or are not matched are ignored.

  • Blocks and strings with matching terminating pairs of square brackets are parsed; the brackets do not affect the parsing of the rule.

IE8 Mode and IE9 Mode (All Versions)

  • Parsing is interrupted when a block, a curly brace, or a parenthesis is encountered before the body of the rule is completely defined after the first curly brace of the rule.