@mixin vertical-gradient( $top, $bottom ) {
  background: $top;
  background: -moz-linear-gradient(top, $top 0%, $bottom 100%);
  background: -webkit-gradient(linear, left top, left bottom, color-stop(0%, $top), color-stop(100%, $bottom));
  background: -webkit-linear-gradient(top, $top 0%, $bottom 100%);
  background: -o-linear-gradient(top, $top 0%, $bottom 100%);
  background: -ms-linear-gradient(top, $top 0%, $bottom 100%);
  background: linear-gradient(top, $top 0%, $bottom 100%);
}

@mixin horizontal-gradient( $top, $bottom ) {
  background: $top;
  background: -moz-linear-gradient(left, $top 0%, $bottom 100%);
  background: -webkit-gradient(linear, left top, right top, color-stop(0%, $top), color-stop(100%, $bottom));
  background: -webkit-linear-gradient(left, $top 0%, $bottom 100%);
  background: -o-linear-gradient(left, $top 0%, $bottom 100%);
  background: -ms-linear-gradient(left, $top 0%, $bottom 100%);
  background: linear-gradient(left, $top 0%, $bottom 100%);
}

@mixin radial-gradient( $outer, $inner, $type: circle ) {
  background: $outer;
  background: -moz-radial-gradient(center, $type cover, $inner 0%, $outer 100%);
  background: -webkit-gradient(radial, center center, 0px, center center, 100%, color-stop(0%, $inner), color-stop(100%, $outer));
  background: -webkit-radial-gradient(center, $type cover, $inner 0%, $outer 100%);
  background: -o-radial-gradient(center, $type cover, $inner 0%, $outer 100%);
  background: -ms-radial-gradient(center, $type cover, $inner 0%, $outer 100%);
  background: radial-gradient(center, $type cover, $inner 0%, $outer 100%);
}