The Following excerpt is borrowed directly from the W3C CSS 2.1 Specification: Ch. 4 Syntax and basic data types. It has been modified from the original code only in that relative paths have been changed to absolute URL’s. Rather than cite specific sections of Ch 4, i thought it best to leave it open to case-by-case usage. My personal recommendation is to review special character encodings, those characters which are allowed to occupy white-space such as \a, and other such special character encodings and their unique purposes.

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• 4.1 Syntax
  • 4.1.1 Tokenization
  • 4.1.2 Keywords
    • 4.1.2.1 Vendor-specific extensions
    • 4.1.2.2 Informative Historical Notes
  • 4.1.3 Characters and case
  • 4.1.4 Statements
  • 4.1.5 At-rules
  • 4.1.6 Blocks
  • 4.1.7 Rule sets, declaration blocks, and selectors
  • 4.1.8 Declarations and properties
  • 4.1.9 Comments
• 4.2 Rules for handling parsing errors
• 4.3 Values
  • 4.3.1 Integers and real numbers
  • 4.3.2 Lengths
  • 4.3.3 Percentages
  • 4.3.4 URL + URN = URI
  • 4.3.5 Counters
  • 4.3.6 Colors
  • 4.3.7 Strings
  • 4.3.8 Unsupported Values
• 4.4 CSS style sheet representation
  • 4.4.1 Referring to characters not represented in a character encoding