@mixin z-layer-0 {
  z-index: -1;
}

@mixin z-layer-1 {
  z-index: 0;
}

@mixin z-layer-2 {
  z-index: 1;
}

@mixin z-layer-3 {
  z-index: 2;
}

@mixin z-layer-4 {
  z-index: 3;
}

@mixin z-layer-5 {
  z-index: 4;
}
