[Post Comments] Input fields can extend beyond the edges of the screen

[kjellr]

Description

Because box-sizing: border-box is not set for the input fields on the comment form, the fields can extend beyond 100%, causing a vertical scroll.

Step-by-step reproduction instructions

This can be reproduced in Twenty Twenty-Two, running WordPress 5.9, Beta 2. Using a small screen, visit any single post that has comments enabled, and scroll down to view the comments form.

This effects any block theme that uses the Post Comments block and doesn't set box-sizing: border-box via CSS.

Screenshots, screen recording, code snippet

Environment info

No response

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

[kjellr]

Related issue: #35704

I'm not sure, but this may need to be fixed in both the Post Comments and Post Comments Form stylesheets.

[kjellr]

Adding to 5.9 Must-Haves since this effects Twenty Twenty-Two.