code: function(range, ctx) {
  				while (ctx && ctx.range) {
  					if (ctx.range.contains(range)) {
  						return ctx.addChild(range);
  					}
  
  					ctx = ctx.parent;
  				}
  
  				// if we are here then given range is a top-level section
  				return root.addChild(range);
  			}
docs: rules are sorted in order they appear in CSS source so we can optimize their nesting routine