ul {
  list-style-type: none;
  margin: 0;
  padding: 0;
  width: 9em;
}

ul li {
  font-family: Arial, sans-serif;
  font-size: smaller;
  margin: 0;
  padding: 0;
  margin-left: 2em;
  background-color: #00cc00;

}

.invisible { display: none; }