code: function(content, pos, isBackward) {
  			// possible case: editor reported that current syntax is
  			// CSS, but it’s actually a HTML document (either `style` tag or attribute)
  			var offset = 0;
  			var subrange = this.styleTagRange(content, pos);
  			if (subrange) {
  				offset = subrange.start;
  				pos -= subrange.start;
  				content = subrange.substring(content);
  			}
  
  			var rules = this.findAllRules(content);
  			var ctxRule = this.matchEnclosingRule(rules, pos);
  
  			if (ctxRule) {
  				return ctxRule.shift(offset);
  			}
  
  			for (var i = 0, il = rules.length; i < il; i++) {
  				if (rules[i].start > pos) {
  					return rules[isBackward && i > 0 ? i - 1 : i].shift(offset);
  				}
  			}
  		}
docs: Locates CSS rule next or before given position
  @param  {String}  content    CSS content
  @param  {Number}  pos        Search start position
  @param  {Boolean} isBackward Search backward (find previous rule insteaf of next one)
  @return {Range}