ul {
  list-style-type: none;
  margin: 0;
  padding: 0;
  width: 200px;
  background-color: #f1f1f1;
}

li a {
  display: block;
  color: #000;
  padding: 8px 16px;
  text-decoration: none;
}

li a.active {
  background-color: lightgray;
  color: black;
}

li a:hover:not(.active) {
  background-color: #555;
  color: white;
}

body {
  font-family: Helvetica, Geneva, Arial, SunSans-Regular, sans-serif;
}

ul.navbar li {
  background: white;
  margin: 0.1em 0;
  padding: 0.1em;
  border-right: 1em solid black
}

ul.navbar a {
  text-decoration: none
}

a:link {
  color: blue
}

a:visited {
  color: gray
}

.scrollable {
    height: 440px; /* or any value */
    overflow-y: auto;
}