Mobile Admin Menu overlaps main content and #wpfooter text when open

[hameem1102]

Environment
WordPress Version: 7.2-beta1
Device / OS: iOS / Safari Mobile

Issue Description
When viewing the WordPress Admin dashboard on a mobile screen with the sidebar navigation menu expanded (.wp-responsive-open), the dark left sidebar (#adminmenuwrap) overlays directly on top of the main content area (#wpcontent) and footer (#wpfooter).

Specifically:

1. Footer Text Truncation: The left side of the admin footer text (#wpfooter) is covered and cut off by the dark sidebar background rather than shifting horizontally or being hidden.
2. Layout Overlap: The stacking context (z-index) and responsive positioning cause the sidebar to obscure the content layer instead of pushing the content container or displaying a clean full-screen backdrop.

Steps to Reproduce

1. Log into the WordPress Admin area on a mobile browser
2. Tap the hamburger icon (≡) in the top admin bar to open the responsive side menu.
3. Scroll down to the bottom of the page (e.g., Comments or Dashboard page).
4. Observe the left alignment of the footer text under the dark menu background.

Expected Behavior
When the responsive mobile menu opens, #wpfooter and main content should either be offset (padding-left / margin-left), covered by a unified backdrop overlay, or hidden to prevent partially readable, truncated text.

[sabernhardt]

This is related to r63642 showing the footer on small screens now.

The main content area moves with a negative right positioning:

	.wp-responsive-open #wpbody {
		right: -16em;
	}

Assigning the same rule to .wp-responsive-open #wpfooter did not work for me, but I was able to achieve the positioning with a positive left value:

	.wp-responsive-open #wpfooter {
		left: 16em;
	}