I don't think I can. I've tried changing the face options, but I didn't
find a way to customize it the way I want, with different backgrounds or
font-weight. For example, I can't set the `mode-line-buffer-id` of
`mode-line` face to have bold font and the `mode-line-inactive` to have a
font without bold.

I'm not sure how I can customize the way I want with
`mode-line-buffer-identification` yet, so maybe that's why having another
face to customize the inactive state still makes sense. I also found this
discussion:
https://emacs.stackexchange.com/questions/10033/change-mode-line-buffer-id-face-for-inactive-windows
- but I don't think there's a solution there.

On Sun, Jan 30, 2022 at 5:33 PM Lars Ingebrigtsen <larsi@gnus.org> wrote:

> José Júnior <jjnilton@gmail.com> writes:
>
> > Yes, it's exactly that. If I want to set a different background color
> > for the `mode-line-buffer-id` when the buffer is inactive, I can't do
> > it with the faces options of the `mode-line` group.
>
> Can't you achieve that by redefining `mode-line-buffer-id' to inherit
> from mode-line-inactive with the proper shadowings?
>
> If that's not sufficient, you can alter
> `mode-line-buffer-identification' to return whatever you wish, so I
> don't think another face here is necessary.
>
> --
> (domestic pets only, the antidote for overdose, milk.)
>    bloggy blog: http://lars.ingebrigtsen.no
>