Hi everyone,
The reponsive MonoBook project is being deployed next week with the normal MediaWiki train. It gives MonoBook a mobile layout for smaller screens, so we can use the same code base to support both layouts (same as Timeless).
There are some more details on Phabricator[1]. You can test this out on the Beta Cluster[2] before it gets deployed.
[1] https://phabricator.wikimedia.org/T195625 [2] https://en.wikipedia.beta.wmflabs.org/wiki/Main_Page?useskin=monobook
Thanks, -- Legoktm