.background-image-bottom {
  position: absolute;
  top: calc(100% - 610px);
  z-index: -1;
}

@media screen and (max-width: 600px) {
  .background-image-bottom-sp {
    display: block;
    position: absolute;
    top: calc(100% - 200px);
    z-index: -1;
  }

  .opt-pc_2clm > li:nth-child(-n + 2) {
    margin-top: 34px;
  }
}