text: const raster = new ol.layer.Tile({
    source: new ol.source.OSM()
  });
  
  const vector = new ol.layer.Vector({
    source: new ol.source.Vector({
      format: new ol.format.GeoJSON(),
      url: 'data/geojson/countries.geojson'
    })
  });
  
  const map = new ol.Map({
    layers: [raster, vector],
    target: 'map2d',
    view: new ol.View({
      center: [0, 0],
      zoom: 2
    })
  });
  
  
  const ol3d = new olcs.OLCesium({map, target: 'map3d'});
  ol3d.setEnabled(true);
  
  
  
  const selectionStyle = new ol.style.Style({
    fill: new ol.style.Fill({
      color: [255, 255, 255, 0.6]
    }),
    stroke: new ol.style.Stroke({
      color: [0, 153, 255, 1],
      width: 3
    })
  });
  
  let selectedFeature;
  map.on('click', (e) => {
    if (selectedFeature) {
      selectedFeature.setStyle(null);
    }
    selectedFeature = map.forEachFeatureAtPixel(
        e.pixel,
        (feature, layer) => feature);
    if (selectedFeature) {
      selectedFeature.setStyle(selectionStyle);
    }
  });
  
  