<https://wpzone.co/wordpress-and-divi-code-snippets/display-woocommerce-products-in-single-column-on-mobile-devices/>

/* START Woocommerce single column on mobile */
@media (max-width: 767px) {
body.et-db #et-boc .et-l .et_pb_shop ul.products.columns-1
li.product,
body.et-db #et-boc .et-l .et_pb_shop ul.products.columns-2
li.product,
body.et-db #et-boc .et-l .et_pb_shop ul.products.columns-3
li.product,
body.et-db #et-boc .et-l .et_pb_shop ul.products.columns-4
li.product,
body.et-db #et-boc .et-l .et_pb_shop ul.products.columns-5
li.product,
body.et-db #et-boc .et-l .et_pb_shop ul.products.columns-6
li.product,
body.et-db #et-boc .et-l .et_pb_wc_related_products
ul.products.columns-1 li.product,
body.et-db #et-boc .et-l .et_pb_wc_related_products
ul.products.columns-2 li.product,
body.et-db #et-boc .et-l .et_pb_wc_related_products
ul.products.columns-3 li.product,
body.et-db #et-boc .et-l .et_pb_wc_related_products
ul.products.columns-4 li.product,
body.et-db #et-boc .et-l .et_pb_wc_related_products
ul.products.columns-5 li.product,
body.et-db #et-boc .et-l .et_pb_wc_related_products
ul.products.columns-6 li.product,
body.et-db #et-boc .et-l .et_pb_wc_upsells ul.products.columns-1
li.product,
body.et-db #et-boc .et-l .et_pb_wc_upsells ul.products.columns-2
li.product,
body.et-db #et-boc .et-l .et_pb_wc_upsells ul.products.columns-3
li.product,
body.et-db #et-boc .et-l .et_pb_wc_upsells ul.products.columns-4
li.product,
body.et-db #et-boc .et-l .et_pb_wc_upsells ul.products.columns-5
li.product,
body.et-db #et-boc .et-l .et_pb_wc_upsells ul.products.columns-6
li.product {
width: 100%!important;
margin-right: 0%!important;
}
.woocommerce-page ul.products li.product:nth-child(n) {
margin: 0 0 11.5%!important;
width: 100%!important;
}
}
/* END Woocommerce single column on mobile */
Code language: CSS (css)