There is a new in-progress design/UX for the mediawiki.ui buttons: https://www.mediawiki.org/wiki/File:Agora_specs.pdf . This includes a new appearance and different CSS class names (see http://www.mail-archive.com/design@lists.wikimedia.org/msg00011.html and https://www.mediawiki.org/wiki/Wikimedia_Foundation_Design/Agora_Control_Library/Behavior).
These updated styles and class names need to be implemented in core. This blocks bug 54360, but can be done before bigger parts of that (e.g. mediawiki.ui dialogs).
Version: 1.23.0
Severity: normal