// Set element positioning in a single statement

@mixin position($position: relative, $coordinates: null null null null) {

  @if type-of($position) == list {
    $coordinates: $position;
    $position: relative;
  }

  $coordinates: unpack($coordinates);

  $offsets: (
    top:    nth($coordinates, 1),
    right:  nth($coordinates, 2),
    bottom: nth($coordinates, 3),
    left:   nth($coordinates, 4)
  );

  position: $position;

  @each $offset, $value in $offsets {
    @if is-length($value) {
      #{$offset}: $value;
    }
  }
}