@mixin box-shadow($shadow…) {

@if $enable-shadows {
  $result: ();

  @each $value in $shadow {
    @if $value != null {
      $result: append($result, $value, "comma");
    }
    @if $value == none and length($shadow) > 1 {
      @warn "The keyword 'none' must be used as a single argument.";
    }
  }

  @if (length($result) > 0) {
    box-shadow: $result;
  }
}

}