/*  from api.mapbox.com/mapbox.js/plugins/leaflet-markercluster/v0.4.0/MarkerCluster.css */
.leaflet-cluster-anim .leaflet-marker-icon, .leaflet-cluster-anim .leaflet-marker-shadow {
    -webkit-transition: -webkit-transform 0.3s ease-out, opacity 0.3s ease-in;
    -moz-transition: -moz-transform 0.3s ease-out, opacity 0.3s ease-in;
    -o-transition: -o-transform 0.3s ease-out, opacity 0.3s ease-in;
    transition: transform 0.3s ease-out, opacity 0.3s ease-in;
}