.WINDOWS::before {
  content: "";
  display: inline-block;
  width: 20px;
  height: 20px;
  background-image: url("/windows.png");
  background-size: contain;
  background-repeat: no-repeat;
  margin-right: 6px;
  vertical-align: middle;
}

.MACINTOSH::before {
  content: "";
  display: inline-block;
  width: 20px;
  height: 20px;
  background-image: url("/apple.png");
  background-size: contain;
  background-repeat: no-repeat;
  margin-right: 6px;
  vertical-align: middle;
}

.PROFESORES::before {
  content: "";
  display: inline-block;
  width: 20px;
  height: 20px;
  background-image: url("/teacher.png");
  background-size: contain;
  background-repeat: no-repeat;
  margin-right: 6px;
  vertical-align: middle;
}