.dimmer {
  display: none;
}

+tablet-mobile() {
  .dimmer {
    background: black;
    height: 100%;
    left: 100%;
    opacity: 0;
    top: 0;
    width: 100%;
    z-index: $zindex-2;
    transition: opacity 1s;
  }

  #sidebar.on + .dimmer {
    position: fixed;
    display: block;
    opacity: .3;
    transform: translateX(-100%);
  }
}