Hello There!
Hope you are doing good!
Please follow the below step to add custom CSS that changes the background color of the newsletter section, you can also set image instead of color using background property.
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_newsletter{
background: black !important;
}
Hope this helps!
Have a great day ahead!
Regards,
Team ProDesigns