How to change appearance of unread mail number notification?

I am finishing up an upgrade from eM Client ver 9 to 10.

I’ve worked my way through the settings and have one niggle I’d like to change.

In ver 9, in the “mail” list, the unread mail number is posted next to each folder. The text was white in a small gray box. I liked it.

In ver 10, the unread mail is now displayed in a blue font, without a box.

While workable, I would really like to go back the the gray box/white text option. It’s just easier for my ageing eyes.

If that is not possible, I’d like to at least try other colors and font sizes. I found nothing in settings.

I slogged my way through the themes editor. In it’s hundreds of options, most made no sense, and I found nothing that looked like it addressed my concern,

As usual, google searches provided many pages of results, with none of them relevant.

I would appreciate if someone could point me in the right direction.

Thank you, Z