Use stretch with compass

By importing compass/layout in order to get more mixins and functions, one of them are Stretch which stretches the element to instead of writing a absolute position and top,right,bottom,left. without any arguments the function default values are 0.

@import "compass";
@import "compass/layout";
.bio {
  position: relative;
  &:after {
    background: rgba(black, 0.3);
    content: "";
    position: absolute;
		@include stretch(10px, 5px, 10px, 5px);
  }
}