parsley/app/assets/stylesheets/star_rating.scss

span.star-rating {

  display: inline-block;
  color: gold;
  cursor: default;
  position: relative;
  white-space: nowrap;

  .empty-set {
    color: gray;
    opacity: 0.5;
  }

  .filled-set {
    overflow-x: hidden;
    position: absolute;
    top: 0;
    left: 0;
  }

  span.star {

    @extend .glyphicon;

    &.empty {
      @extend .glyphicon-star-empty;
    }

    &.full {
      @extend .glyphicon-star;
    }
  }

}