@mixin gradient($orientation, $startColor, $endColor) {
  background: $endColor; /* for non-css3 browsers */

  $orientation-reverse: 180deg;
  @if $orientation == 'to bottom' {
    $orientation-reverse: 0deg;
    $orientation: 180deg;
  }
  @if $orientation == 'to top' {
    $orientation-reverse: 180deg;
    $orientation: 0deg;
  }
  @if $orientation == 'to left' {
    $orientation-reverse: 270deg;
    $orientation: 90deg;
  }
  @if $orientation == 'to right' {
    $orientation-reverse: 90deg;
    $orientation: 270deg;
  }

  background: -webkit-linear-gradient($orientation, $orientation-reverse, $startColor, $endColor); /* для webkit-браузеров */
  background: -moz-linear-gradient($orientation, $startColor, $endColor); /* для firefox 3.6+ */
  background: -o-linear-gradient($orientation, $startColor, $endColor); /* для Opera 11.10+ */
  background: -ms-linear-gradient($orientation, $startColor, $endColor); /* для IE10+ */
  background: linear-gradient($orientation, $startColor, $endColor);
}