Last parent selector in SASS (like & but only the last one)

_utilities.scss

// same as &, but applies the last (closest) parent only
// usage: @include u-direct-parent('.parent'<, ...>) {}
@mixin u-direct-parent($parent-selectors...) {
  @each $parent-selector in $parent-selectors {
    $current-sequences: &;
    $new-sequences: ();

    @each $sequence in $current-sequences {
      $current-selector: nth($sequence, -1);
      $prepended-selector: join($parent-selector, $current-selector);
      $new-sequence: set-nth($sequence, -1, $prepended-selector);
      $new-sequences: append($new-sequences, $new-sequence, comma);
    }
    
    @at-root #{$new-sequences} {
      @content;
    }
  }
}

From here: https://stackoverflow.com/a/30687813/102397