.woocommerce-product-gallery__image{
    width: 25%;
    float: left;
}
.summary.entry-summary{
    width: 75%;
    float: left;
}
.woocommerce-Tabs-panel--description{
    width: 100%;
    float: left;
}

@media (max-width: 767px) {
    .woocommerce-product-gallery__image{
        width: 100%;
        float: left;
    }
}