code: function getCSSRules(doc) {
      var styles = doc.getElementsByTagName('style'),
          allRules = { },
          rules;
  
      // very crude parsing of style contents
      for (var i = 0, len = styles.length; i < len; i++) {
        var styleContents = styles[0].textContent;
  
        // remove comments
        styleContents = styleContents.replace(/\/\*[\s\S]*?\*\//g, '');
  
        rules = styleContents.match(/[^{]*\{[\s\S]*?\}/g);
        rules = rules.map(function(rule) { return rule.trim() });
  
        rules.forEach(function(rule) {
          var match = rule.match(/([\s\S]*?)\s*\{([^}]*)\}/),
              rule = match[1],
              declaration = match[2].trim(),
              propertyValuePairs = declaration.replace(/;$/, '').split(/\s*;\s*/);
  
          if (!allRules[rule]) {
            allRules[rule] = { };
          }
  
          for (var i = 0, len = propertyValuePairs.length; i < len; i++) {
            var pair = propertyValuePairs[i].split(/\s*:\s*/),
                property = pair[0],
                value = pair[1];
  
            allRules[rule][property] = value;
          }
        });
      }
  
      return allRules;
    }
docs: Returns CSS rules for a given SVG document
  @static
  @function
  @memberOf fabric
  @method getCSSRules
  @param {SVGDocument} doc SVG document to parse
  @return {Object} CSS rules of this document