.price--on-sale .price-item--regular{
    text-decoration: none!important;
}

.price--on-sale .price-item--regular .money{
    text-decoration: line-through;
    font-size: 21px;
    line-height: 23px;
}

@media screen and (max-width: 480px) {
    .price--on-sale .price-item--regular .money{
        font-size: 13px;
        line-height: 15px;
    }
}