@mixin nb-hidden() {
  @each $bp-key, $bp-value in $nb-breakpoints {
    @include nb-respond-to($bp-key) {
      .#{$nb-namespace}u-hidden#{$nb-breakpoint-class}#{$bp-key} {
        display: none !important;
      }
    }
    @include nb-respond-to('max-#{$bp-key}') {
      .#{$nb-namespace}u-hidden#{$nb-breakpoint-class}max-#{$bp-key} {
        display: none !important;
      }
    }
  }
}