Change color of google map : I have ambeded my map in a website , Now I want to change color of google map to  `dark` , as given in google maps. I am trying to do this but dont know where to given style I have to apply
my code of init map is .I think I have to change in this 

      _initMap: function() {
                var self= this, options  = this.options,
                    centerPosition = new google.maps.LatLng(options.latitude, options.longitude);
    
                /**
                 * map
                 * @type {google.maps.Map}
                 */
                this.map = new google.maps.Map(this.element[0], {
                    zoom: parseFloat(options.zoom_level),
                    center: centerPosition,
                    minZoom: options.minZoom,
                    maxZoom: options.maxZoom
                });
    
                this.storePopupTmpl = mageTemplate($(options.storePopupTemplate).html());
    
                /**
                 * infor windopw
                 * @type {google.maps.InfoWindow}
                 */
                this.infowindow = new google.maps.InfoWindow({
                    //maxWidth: 250,
                    //disableAutoPan: true,
                    maxWidth: 450,
                    minWidth: 350,
                });

