Hello @Stelio,
You can change the color of those notices using Custom CSS. Please copy and paste the following CSS code to XStore >> Theme Options >> Theme Custom CSS >> Global CSS and then clear your browser cache to view the changes.
.woocommerce-account .woocommerce-Message.woocommerce-Message--info.woocommerce-info {
background-color: #116641 !important;
}
Note: You can modify the color code in the given code to suit your needs.
Best Regards,
8Theme’s Team