ul.demo:after {
  display: block;
  content: "";
  clear: both;
}

ul.demo>li {
  float: left;
  position: relative;
}

ul.demo a {
  display: block;
  text-decoration: none;
  height: 40px;
  line-height: 38px;
  padding: 0 15px;
  background-color: #f7f7f7;
  color: #333;
}

ul.demo a:hover { background-color: #f0f0f0; }

ul>li ul {
  display: none;
  position: absolute;
  width: 200px;
}

ul>li:hover ul { display: block; }