Openlayer地图的样式颜色：道路，地形等

Question

我想从Google Map迁移到Openlayer Map v5。我需要一些帮助来修改地图的颜色或对象，例如：道路，地形，水。

基本代码：

 <script>
var map = new ol.Map({
    view: new ol.View({center: ol.proj.transform([13.12754,45.68177], 'EPSG:4326', 'EPSG:3857'), zoom:12}),
    layers: [new ol.layer.Tile({
            source: new ol.source.OSM()
    })],
    target:'map'
});


var markers = new ol.layer.Vector({
  source: new ol.source.Vector(),
  style: new ol.style.Style({
    image: new ol.style.Icon({
      anchor: [0.5, 1],
        src: 'images/marker.png'
    })
  })
});
map.addLayer(markers);      

var marker = new ol.Feature(new ol.geom.Point(ol.proj.fromLonLat([13.12754,45.68177])));
markers.getSource().addFeature(marker);     

</script>