SASS: Mixin Linear Gradient

mixin-linear-gradient.scss

@mixin linear-gradient( $start: #f1f1f1, $from: 0%, $stop: #d9d9d9, $to: 100% ) {
  background: $start;
  background: -webkit-gradient(linear, left top, left bottom, from(ie-hex-str($start)), to(ie-hex-str($stop)));
  background: -moz-linear-gradient(center top, $start $from, $stop $to);
  background: -moz-gradient(center top, $start $from, $stop $to);
  background: -webkit-linear-gradient(top, $start $from,$stop $to);
  background: -o-linear-gradient(top, $start $from,$stop $to);
  background: -ms-linear-gradient(top, $start $from,$stop $to);
  background: linear-gradient(to bottom, $start $from,$stop $to);
  filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#{ie-hex-str($start)}', endColorstr='#{ie-hex-str($stop)}',GradientType=0 );
}