Yes, it's very simple.

For frame color it uses the color of the ad creator's role tag, but this can be changed.

This is defined in lines 78 and 80 of the file:

yoursite.com/ow_plugins/memberads/views/components/item_list.html

There you must replace {$item.avatarData.labelColor} with the color you want, red, green, black... or the number of color you want.

This is twice if you want to differentiate paid member ads from free member ads.

The background color is fixed, it is also twice for the same reason, in the lines 94 and 104 of the file:

yoursite.com/ow_plugins/memberads/static/themes/default/memberads.css

Just replace the color number, where it says

background-color: #fbf9e3f7;

replace fbf9e3f7 with the color number you want, or the color name (red, blue, green...) if it is a basic color.

Here you can select colors:

https://htmlcolorcodes.com/es/selector-de-color/
https://www.w3schools.com/colors/colors_picker.asp
https://pinetools.com/image-color-picker

Thank you so much Patricia, I found it now too.

I also commented on the topic that the plugin is not responsive.

Unfortunately, an ad falls outside the picture on a smartphone.

If you give me more information to be able to reproduce the problem I can help you, or give me a user access or something, by email if you want: admin@somoscd.es