.popup {
  background-color: rgba(68, 68, 68, .8);
  display: none; /* 初期非表示 */
  height: 100%;
  left: 0;
  position: fixed;
  top: 0;
  width: 100%;
  z-index: 10000;
}
.popup-overlay {
  align-items: center;
  display: flex;
  flex-direction: column;
  height: 100%;
  justify-content: center;
}
.popup-content {
  background: #fff;
  width: 60%;
  text-align: center;
}
@media screen and (max-width: 768px) {
  .popup-content {
    width: 80%;
  }
}
.popup-close {
  background: none;
  border: none;
  color: #fff;
  cursor: pointer;
  font-size: 40px;
}
.popup img {
  max-width: 100%;
}