Changeset 27195

Once upon a time not long ago,
The admin CSS was merged in #18314.
After a couple years as it stood,
The mess it had become just was no good.
One day we realized Grunt is pretty cool,
And said "we should use this as our build tool!"
Now we can maintain separate files with ease,
Using @import and cssmin meets all our needs.
Welcome to the future of the WordPress stylesheets,
And thanks to Slick Rick for the beats.

props jorbin for the initial patch.
fixes #26669.