code: protected boolean isPseudoSpecialCase(String identifier) {
          return "first-line".equalsIgnoreCase(identifier) ||
                  "first-letter".equalsIgnoreCase(identifier) ||
                  "before".equalsIgnoreCase(identifier) ||
                  "after".equalsIgnoreCase(identifier);
      }
docs: pseudo (Special cases)
  // '::' starts a pseudo-element, ':' a pseudo-class
  // Exceptions: :first-line, :first-letter, :before and :after.