@mixin box-shadow($shadow…) {

@if $enable-shadows {
  $result: ();
  @if (length($shadow) == 1) {
    // We can pass `@include box-shadow(none);`
    $result: $shadow;
  } @else {
    // Filter to avoid invalid properties for example `box-shadow: none, 1px 1px black;`
    @for $i from 1 through length($shadow) {
      @if nth($shadow, $i) != "none" {
        $result: append($result, nth($shadow, $i), "comma");
      }
    }
  }
  @if (length($result) > 0) {
    box-shadow: $result;
  }
}

}