<div id="map"></div>

body { margin: 0; padding: 0; }
#map { position: absolute; top: 0; bottom: 0; width: 100%; }

mapboxgl.accessToken = 'pk.eyJ1IjoieW9jaGkiLCJhIjoiY2xmd2k3MDFzMDB5bDNlcDZjazB1dHR1cSJ9.3bsAuOobDf15EVa4LfHmsQ';
const map = new mapboxgl.Map({
  container: 'map', 
  center: [-74.5, 40],
  zoom: 9
});

map.addSource('streets', {
  type: 'vector',
  url: 'mapbox://mapbox.mapbox-streets-v8'
});
  
map.addLayer({
  id: 'road',
  type: 'line',
  source: 'streets',
  'source-layer': 'road',
  paint: {
    'line-color': '#00ff00',
    'line-width': 3,
  }
});