Focus outline width inconsistency in Site Editor

[Infinite-Null]

Description

In the Site Editor's Design/Navigation panel, there's a visual inconsistency between the focus outline and the main highlighted/selected element. The focus outline appears to have a different width than the background highlight of the selected navigation item, creating a misaligned appearance.

Step-by-step reproduction instructions

1. Navigate to the WordPress admin dashboard
2. Go to Appearance > Editor
3. Select Navigation from the design options
4. Select any one navigation item from list
5. Observe the focus outline width compared to the selected/highlighted item background

Expected behavior: The focus outline should align properly with the selected item background.
Actual behavior: The focus outline and selected item background have different widths, creating visual misalignment

Screenshots, screen recording, code snippet

Environment info

• WordPress: 6.9-alpha-60166
• Plugins:
  • Gutenberg 21.1.0
• PHP: 8.2.28
• Theme: Twenty Twenty-Five 1.2
• OS: macOS
• Server: Apache/2.4.62 (Debian)
• Database: mysqli (Server: 11.8.2-MariaDB-ubu2404 / Client: mysqlnd 8.2.28)
• Browser: Chrome 138.0.0.0

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

Please confirm which theme type you used for testing.

• Block
• Classic
• Hybrid (e.g. classic with theme.json)
• Not sure

[t-hamano]

Closing as a duplicate of #69189.