Hide "Skip to Toolbar" shortcut on small screens within admin

[sabernhardt]

At the 782px breakpoint, common.css hides the side admin menu. Then there is no focusable content between the "Skip to Toolbar" shortcut link and its target, which makes the link unhelpful.

Hides "Skip to Toolbar" link when it has nothing to skip past.

Trac 63118

[joedolson]

Given that the admin sidebar now auto-hides when focus isn't inside it, I think you're right that there is no case where this skip link will still be useful.

We just need to make sure to carefully consider & test all possibilities before doing this, to be sure that we're not removing an access point that we haven't considered.

[abcd95]

This report validates that the indicated patch works as expected.

Patch tested: ​PR 8528

Environment

• WordPress: 6.8-beta2-59971-src
• PHP: 8.2.25
• Server: nginx/1.27.2
• Database: mysqli (Server: 8.4.4 / Client: mysqlnd 8.2.25)
• Browser: Chrome 137.0.0.0
• OS: macOS
• Theme: Twenty Twenty-Five 1.1

Actual Results

✅ Skip link properly hidden on small screens (<=782px) where there is not content to skip

[joedolson]

Discussed this with @alh0319 at WCEU to get a second opinion, and we agree that there is no longer any case where this skip link is needed on small screens. Marking for commit.

@mleray Do you have a WordPress profile ID I can use to give props for this contribution?

[sabernhardt]

In 60286:

Administration: Hide skip to toolbar link on small viewports.

Since r55326, the admin sidebar autocloses on small viewports when focus exits the sidebar. Because of this, there is no case where the Skip to Toolbar link will have any function on small viewports.

Props sabernhardt, abcd95, alh0319, mleray, joedolson.
Fixes #63118.

Committed in r60286