div {
  position: relative;
}
div:before {
  content: '';
  position: absolute;
  left: 5px;
  top: 50%;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: transparant;
  transform: translateY(-50%);
}
div.active:before {
  background: green;
}