#page.system.in {
  background: url(../img/system/bg.png) no-repeat center top/100%, #22AC38;
}
#page.system.in .door-header-bg:before {
  display: none;
}

@media screen and (max-width: 767px) {
  #page.system.in {
    background: none;
  }
  #page.system.in .door-nav-item:nth-child(n+2) .door-nav-ttl {
    color: #000;
  }
}