@mixin transparent($color, $alpha) {
$rgba: rgba($color, $alpha);
$ie-hex-str: ie-hex-str($rgba);
background-color: transparent;
background-color: $rgba;
filter:progid:DXImageTransform.Microsoft.gradient(startColorstr=#{$ie-hex-str},endColorstr=#{$ie-hex-str});
zoom: 1;
}