Add opacity to a class in your SASS file using the Opacity SASS Mixin.

Opacity SASS Mixin.scss

// -----------------------------------------

	// Opacity
	
// -------------------------------------------
 
// example: @include opacity(0.8);

@mixin opacity($opacity) {
  opacity: $opacity;
  $opacity-ie: $opacity * 100;
  filter: alpha(opacity=$opacity-ie); //IE8
}