.menu ul {
  list-style-type: none;
  margin: 0;
  padding: 0;
  overflow: hidden;
  background-color: #333;

  position: -webkit-sticky; /* Safari */
  position: sticky;
  top: 0;
}

.menu li {
  float: left;
}

.menu li a {
  display: block;
  color: white;
  text-align: center;
  padding: 14px 16px;
  text-decoration: none;
}

/* Change the link color to #111 (black) on hover */
.menu li a:hover {
  background-color: #111;
  padding: 14px 16px;
}

.active {
  background-color: #4CAF50;
}