styles.css

body {
  margin: 0;
  padding: 0;
}

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

.marker {
  background-color: #fff;
  background-size: cover;
  width: 30px;
  height: 30px;
  border-radius: 75%;
  cursor: pointer;
}

.mapboxgl-popup {
  max-width: 400px;
  font: 12px/20px "Helvetica Neue", Arial, Helvetica, sans-serif;
}

#menu {
  background: #fff;
  position: absolute;
  z-index: 1;
  top: 10px;
  left: 10px;
  border-radius: 3px;
  width: 225px;
  border: 1px solid rgba(0, 0, 0, 0.4);
  font-family: "Open Sans", sans-serif;
}

#menu a {
  font-size: 13px;
  color: #000;
  display: block;
  margin: 0;
  padding: 0;
  padding: 10px;
  text-decoration: none;
  border-bottom: 1px solid rgba(0, 0, 0, 0.25);
  text-align: center;
}

#menu a:last-child {
  border: none;
}

#menu a:hover {
  background-color: #dcdcdc;
  color: #404040;
}

#menu a.active {
  background-color: #696969;
  color: #ffffff;
}

#menu a.active:hover {
  background: #a9a9a9;
}

.legend {
  background-color: #fff;
  border-radius: 3px;
  bottom: 30px;
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.1);
  font: 12px/20px "Helvetica Neue", Arial, Helvetica, sans-serif;
  padding: 10px;
  position: absolute;
  right: 10px;
  z-index: 1;
}

.legend h4 {
  margin: 0 0 10px;
}

.legend div span {
  border-radius: 50%;
  display: inline-block;
  height: 10px;
  margin-right: 5px;
  width: 10px;
}