source/misc/embedded_libs/fmt-8.1.1/doc/bootstrap/mixins/opacity.less
browsing at commit = 081d847ab67afcf2def54c77c8601af6b215b5b8
// Opacity
.opacity(@opacity) {
opacity: @opacity;
// IE8 filter
@opacity-ie: (@opacity * 100);
filter: ~"alpha(opacity=@{opacity-ie})";
}