_gradients.css.scss

@mixin gradient($from, $to) {
  /* fallback/image non-cover color */
  background-color: $from;

  /* Firefox 3.6+ */
  background-image: -moz-linear-gradient($from, $to);

  /* Safari 4+, Chrome 1+ */
  background-image: -webkit-gradient(linear, 0% 0%, 0% 100%, from($from), to($to));

  /* Safari 5.1+, Chrome 10+ */
  background-image: -webkit-linear-gradient($from, $to);

  /* Opera 11.10+ */
  background-image: -o-linear-gradient($from, $to);
}

example.css.scss

.my_div {
  @include gradient($background_color, white);
}