ul {
  list-style-type: none;
  margin: 0;
  padding: 0;
  overflow: hidden;
  background-color: #333333;
  position: fixed; /* Make it stick, even on scroll */
  top: 0;
 
  width: 100%;
}

li {
  float: left;
  font-size: 125%;
}

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

li a:hover {
  background-color: #555;
  color: white;
}