Calendar styles are broken in the post publish panel

[octaedro]

Description

The calendar styles in the post-publish panel, when expanding the scheduling section, look broken.

Step-by-step reproduction instructions

1. In a brand new JN site, install GB 17.9.0
2. Go to Posts > Add New Post
3. Add a Title and press Publish.
4. The post-publish panel will be visible.
5. Press Publish: Immediately.
6. The calendar will be visible, but it will be cut.

Screenshots, screen recording, code snippet

Environment info

It's happening on GB 17.9.0

Please confirm that you have searched existing issues in the repo.

Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

Yes

[annezazu]

I can replicate this with 6.5 RC2. Adding to the board.

[t-hamano]

I believe this issue is a regression caused by #55502. This can be reproduced for the first time in WP6.5.

In #55502, the button size was increased from 28px to 32px, which seems to have caused it to overflow the sidebar width.

Below is a screenshot on Windows OS, but the Sunday column is completely hidden.

The following is a screenshot from WP6.4, and although the overflow itself does not occur, the calendar elements are sticking out of the grid layout, so some fundamental adjustment will be required.

[getdave]

I believe this issue is a regression caused by #55502.

Can we revert the change to day sizing introduced in that PR and see if it fixes? We can then ship that fix in 6.5 and seek a more robust solution to enlarging the text size during 6.6 cycle.

[t-hamano]

I submitted a PR: #59990

[t-hamano]

@getdave #59990, which fixes this issue, has been merged. We didn't make it in time to ship to RC3, but I don't think this issue is critical, so 6.5.1 might be fine.

[getdave]

I'm happy punting this to 6.5.1 - cc'ing @fabiankaegy and @annezazu for confirmation.

[annezazu]

I'm okay with that 👍🏼 The functionality still works so it feels less mission critical.