How to Add Icon to Category on WordPress

.class-name ul {
  list-style: none;
  padding: 0;
    color:#002468;
}

.class-name li {
  padding-left: 1.3em;
    font-weight: bold;
    font-size:18px;
}

.class-name li:before {
    font-size:16px;
  content: "\f138";
  font-family: FontAwesome;
  display: inline-block;
  margin-left: -1.3em;
  width: 1.3em;
}