.nav_cont {
  display: none;
}
@media screen and (max-width: 750px) {
  .all_cont_box {
    width: 100%;
    overflow: hidden;
  }
  .all_cont_box .all_cont_box_page {
    width: 200vw;
    transition: transform 300ms;
    display: flex;
  }
  .all_cont_box .all_cont_box_page > div {
    width: 50%;
  }
  .all_cont_box .all_cont_box_page .nav_cont {
    display: block;
  }
}