gistfile1.txt

.b-detail-product__price-container .b-compare__link
    &::before {
        background: url($sprite-url) no-repeat -337px -166px;
        width: 12px;
        height: 16px;
        position: absolute;
        top: 2px;
        left: 0;
        content: "";
    }
     
    // it does not works
    &.in_compare::before {
        background: url($sprite-url) no-repeat -355px -166px;
    }
}