Replacing all colors with current WikimediaUI palette ones.
Also:
- changing two files over to LESS in order to
- make use of central gradient mixin instead of one with
unnecessary vendor extensions and
- concatenating selectors in one occurrence.
Bug: T174237
Change-Id: I5d302f29b079f6abdba5abf3b58d6ba254e1a4ac
Without this isolation the input method name can be shown
incorrectly when its direction is different from the direction
of the "How to use" element.
This only breaks on Firefox; Chrome somehow shows it correctly
without isolation, but isolation makes sense in any case.
Change-Id: I3c906f4fdd259b94f909b36bab91474cae2971af
