wp-signup and wp-activate page ui looking broken

[umesh.nevase]

I visited the pages for registration and activation. There is no left-side gap between the header and footer. It doesn't appear promising. We can add the distance between the header and footer and the left side of the screen.

This issue is coming for 2022,2023,2024 and 2025 theme, FSE themes. for the themes 2021 and before it looks fine.

[umesh.nevase]

wp-activate.php page screenshot

[umesh.nevase]

This pages will appear for MU WordPress. I've enabled Network site settings for Both site and user registration.

• I've enabled Network site settings for Both site and user registration on multisite WordPress.
• There are no space between screen and header/footer.
• The issue is coming for all FSE themes 2022, 2023, 2024, 2025. It looks find theme 2021 and before.
• I've added filter for body classes for both the pages. and added style by using those new classes in this PR.
• We have handle this CSS in theme, there are more chance for improvement for UI on both these pages

(Trac #63499)

Trac ticket:

[sabernhardt]

Block themes typically do not have the header.php and footer.php templates, which makes them default to the wp-includes/theme-compat files. If #55023 can create the header and footer from the theme, that would be a better way to fix this.

If the theme-compat header and footer are centered at 90% width, the styles would need to make sure it only applies with the theme-compat markup. Many classic themes could have elements with ​#header or ​#footer, and at least Twenty Ten's header should not be set to 90%.

[umesh.nevase]

If block theme does not handle it then we have to handle it from WordPress or admin CSS.
I've suggested one approach from PR.
Can we handle body classes by detecting TwentyTen theme and apply CSS according on these 2 pages only?
#header and #footer not used in any theme except TwentyTen theme.

[sabernhardt]

I would add styles in the wp-includes/theme-compat/header.php template such as:

<style>
:where(#header, #footer) {
	padding-left: 5%;
	padding-right: 5%;
}
</style>

• The :where() specificity makes it easier for themes to override the style, especially if it only edits the padding (instead of both margin and a width or max-width).
• Classic themes have required their own header and footer PHP templates for many years. As a result, almost every time someone gets the markup from the theme-compat fallback now should involve these multisite pages with a block theme (and those hopefully would use templates from the theme soon).

If the styles are updated before the real fix can be completed, I would also like to make several ​changes to the markup. That PR on my fork seems about ready to move it to the main wordpress-develop repository for discussion and review. (Should I connect it to this ticket?)

New body classes should not be necessary for this CSS, but they could help on #43536.