_linear-gradient.scss

@mixin linear-gradient($start, $color-stops...) {
  $start: unquote($start);
  $vendors-direction: null;
  $directions: top left bottom right;

  @if str-index($start, "top") > 0 or str-index($start, "left") > 0 or str-index($start, "bottom") > 0 or str-index($start, "right") > 0 {
    $proc: ();
    @for $i from 1 to 4 {
      @if str-index($start, nth($directions, $i)) > 0 {
        $proc: append($proc, nth($directions, if($i < 3, $i + 2, $i - 2)));
      }
    }
    @if str-index($start, "to ") > 0 {
      $vendors-direction: join((), $proc, space);
    } @else {
      $vendors-direction: $start;
      $start: join((), $proc, space);
    }
  } @else if str-index($start, "deg") > 0 {
    $vendors-direction: $start * (-1) + 90deg;
  } @else {
    @warn "A direction is invalid.";
  }

  background-image: -webkit-linear-gradient(unquote($vendors-direction), unquote($color-stops));
  background-image: linear-gradient(unquote($start), unquote($color-stops));
}