function initMap() {
  // Styles a map in night mode.
  var map = new google.maps.Map(document.getElementById('map'), {
    center: {lat: 40.674, lng: -73.945},
    zoom: 12,
    styles: [
      {elementType: 'geometry', stylers: [{color: '#242f3e'}]},
      {elementType: 'labels.text.stroke', stylers: [{color: '#242f3e'}]},
      {elementType: 'labels.text.fill', stylers: [{color: '#746855'}]},
      {
        featureType: 'administrative.locality',
        elementType: 'labels.text.fill',
        stylers: [{color: '#d59563'}]
      },
      {
        featureType: 'poi',
        elementType: 'labels.text.fill',
        stylers: [{color: '#d59563'}]
      },
      {
        featureType: 'poi.park',
        elementType: 'geometry',
        stylers: [{color: '#263c3f'}]
      },
      {
        featureType: 'poi.park',
        elementType: 'labels.text.fill',
        stylers: [{color: '#6b9a76'}]
      },
      {
        featureType: 'road',
        elementType: 'geometry',
        stylers: [{color: '#38414e'}]
      },
      {
        featureType: 'road',
        elementType: 'geometry.stroke',
        stylers: [{color: '#212a37'}]
      },
      {
        featureType: 'road',
        elementType: 'labels.text.fill',
        stylers: [{color: '#9ca5b3'}]
      },
      {
        featureType: 'road.highway',
        elementType: 'geometry',
        stylers: [{color: '#746855'}]
      },
      {
        featureType: 'road.highway',
        elementType: 'geometry.stroke',
        stylers: [{color: '#1f2835'}]
      },
      {
        featureType: 'road.highway',
        elementType: 'labels.text.fill',
        stylers: [{color: '#f3d19c'}]
      },
      {
        featureType: 'transit',
        elementType: 'geometry',
        stylers: [{color: '#2f3948'}]
      },
      {
        featureType: 'transit.station',
        elementType: 'labels.text.fill',
        stylers: [{color: '#d59563'}]
      },
      {
        featureType: 'water',
        elementType: 'geometry',
        stylers: [{color: '#17263c'}]
      },
      {
        featureType: 'water',
        elementType: 'labels.text.fill',
        stylers: [{color: '#515c6d'}]
      },
      {
        featureType: 'water',
        elementType: 'labels.text.stroke',
        stylers: [{color: '#17263c'}]
      }
    ]
  });
}