.acc{
  margin: 60px auto;
  max-width: 750px;
}
@media screen and (max-width: 750px) {
  .acc{
    margin: 30px auto;
  }
}
.acc_item{
  display: block;
  interpolate-size: allow-keywords;
}
.acc_item::details-content{
  height: 0;
  overflow: hidden;
  transition: height 0.5s ease-out, content-visibility 0.5s allow-discrete;
}
.acc_item[open]::details-content{
  height: auto;
  height: calc-size(auto, size);
}
.acc_item[open] .acc_summary::after{
  transform: rotate(-135deg) translate(-50%);
}
.acc_summary{
  font-size: 32px;
  font-family: "A1 Mincho", Georgia, 游明朝, "Yu Mincho", YuMincho, "Hiragino Mincho ProN", HGS明朝E, メイリオ, Meiryo, serif;
  -webkit-appearance: none;
  appearance: none;
  list-style: none;
  cursor: pointer;
  background-color: #E4EBF2;
  padding: 40px;
  text-align: center;
  position: relative;
}
@media screen and (max-width: 750px) {
  .acc_summary{
    font-size: 18px;
    padding: 24px;
  }
}
.acc_summary::-webkit-details-marker {
  display: none;
}
.acc_summary::after{
  border-bottom: 2px solid #777;
  border-right: 2px solid #777;
  content: "";
  display: block;
  width: 24px;
  height: 24px;
  position: absolute;
  right: 8%;
  top: 43%;
  transform: rotate(45deg) translateY(-50%);
  transition-property: transform;
  transition-duration: 0.5s;
}
@media screen and (max-width: 750px) {
  .acc_summary::after{
    width: 8px;
    height: 8px;
  }
}