Hello,
If you use the inspector as explained in the documentation page we gave you, you will see that there is still a CSS rule which define the white background.
#hikashop_category_information_module_ div.hikashop_subcontainer, #hikashop_category_information_module_ .hikashop_rtop *, #hikashop_category_information_module_ .hikashop_rbottom * {
background: #ffffff;
}
That rule is coming the menu configuration (ID 108) since there is no ID for the module.
In any case, you can override that CSS rule in a CSS file and mark it as important.
And regarding the CSS rule that Nicolas gave you ; it should work but I can't find any trace of that rule in your CSS files.
If I add that rule in my browser inspector, I right got a transparent background for the items. So it really solve the issue.
CF :
pasteboard.co/GZGfIg6.png
That's why I'm afraid that you did not add the CSS rule in your override as suggested.
Please understand that we can't help further since we already gave you some help beyond the limit of our support and we can't find element which indicates that you follow the Nicolas instruction.
Regards,