Hello, @Kazi Sabit,
Please copy and paste the below-given CSS code to XStore >> Theme Settings >> Theme Custom CSS and under the Global Custom CSS section and change the value of the color in the given code as per your requirements.
.products-bordered-layout:not(.with-ajax)>div {
border-color: red !important;
}
.etheme_products .row.products.products-loop.products-grid {
border-color: red !important;
}
Regards 8Themes Team.