Opacity – 투명도

@mixin opacity($opacity: 0.5) {
  $opacityMultiplied: ($opacity * 100);

  filter:         alpha(opacity=$opacityMultiplied);
  -ms-filter:     "progid:DXImageTransform.Microsoft.Alpha(Opacity=" + $opacityMultiplied + ")";
  @include css3-prefix('opacity', $opacity);
}

Css3 Prefix

@mixin css3-prefix($property, $value) {
  -webkit-#{$property}: #{$value};
  -khtml-#{$property}: #{$value};
  -moz-#{$property}: #{$value};
  -ms-#{$property}: #{$value};
  -o-#{$property}: #{$value};
  #{$property}: #{$value};
}