@media (min-width: 768px) {
  /* PC */
  .-gradenumber .m-media__btn.unactive {
    position: relative;

    pointer-events: none;
  }
  .-gradenumber .m-media__btn.unactive::after {
    content: '';

    position: absolute;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    transform: none;
    background-color: rgba(0,0,0,.25);
    border-radius: 6px;

    pointer-events: none;
  }
}
@media (max-width: 767px) {
  /* SP */

  .-gradenumber .m-media__btn.unactive {
    position: relative;

    pointer-events: none;
  }
  .-gradenumber .m-media__btn.unactive::after {
    content: '';

    position: absolute;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    transform: none;
    background-color: rgba(0,0,0,.25);
    border-radius: 6px;

    pointer-events: none;
  }
}