body {
  margin: 0;
  font-family: Arial, Helvetica, sans-serif;
}

.topnav {
  overflow: hidden;
  background-color: #666;
  position: fixed;
  top: 0%;
}

.topnav a {
  float: left;
  color: #fff;
  text-align: center;
  padding: 14px 16px;
  text-decoration: none;
  font-size: 17px;
}

.topnav a:hover {
  background-color: #000;
  color: #fff;
}

.topnav a.active {
  background-color: #8000ff;
  color: white;
}