Better focus styles for form elements in the admin. These are purposefully not keyed to admin color schemes, as different colors could communicate a state like an error as opposed to focus. props celloexpressions. fixes #27173.

Built from https://develop.svn.wordpress.org/trunk@27741


git-svn-id: http://core.svn.wordpress.org/trunk@27578 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Make the CSS selector for current playlist item `<img>` more specific so the width is properly constrained.

Hide the `<audio>` element in the playlist to prevent a flicker when loading - MEjs hides the audio element anyway.

See #27525.


Built from https://develop.svn.wordpress.org/trunk@27742


git-svn-id: http://core.svn.wordpress.org/trunk@27579 1a063a9b-81f0-0310-95a4-ce76da25c4cd