Hello There!
Hope you are doing good!
Please follow the below step to add custom CSS that changes the diamond background-color.
1) Please log in to the admin area
2) Go to “Appearance >> Customize >> Additional CSS”.
3) Paste the below code in “Additional CSS” and save it afterward:
#home-page-widget-area .widget.ecommerce_gem_widget_call_to_action .cta-widget::before{
background: black !important;
}
Hope this helps!
Regards,
Team ProDesigns