.has-child {
  position: relative;
}
.has-child .mega_menu {
  /*display: none;*/
  /*position: absolute;*/
  /*top: 100%;*/
  left: 0;
  z-index: 1000;
  background: #fff;
  padding: 1em;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}
.has-child:hover .mega_menu {
  /*display: block;*/
}
/* hoverのズレ対策 */
.has-child {
  padding-bottom: 20px; /* 下方向の余白を少し増やす */
}

.is-animation nav li.has-child ul {
    top: 70px!important;
}

@media (max-width: 900px) {
    #HeaderWrapper #Header .menu-wrapper .drawer-nav {
      opacity: 0;
      visibility: hidden;
      transition: all .3s;
    }
    #HeaderWrapper #Header .menu-wrapper .drawer-nav.open {
      opacity: 1;
      visibility: visible;
      display: unset;
    }
    .has-child .mega_menu {
      display: none;
    }
    .has-child:hover .mega_menu {
        display: none;
    }
    .has-child .mega_menu.open {
      display: block;
    }
    #HeaderWrapper #Header .menu-wrapper .drawer-nav.open {
      display: block;
    }
    .is-animation nav li.has-child ul {
      top: 0px !important;
    }
}
@media (max-width: 900px) {
    .open.ScrollBox {
        overflow-y: scroll;
    }
}