Help make sure relevant editors on the wikis have a decent chance to learn about [[ https://www.mediawiki.org/wiki/Extension:TemplateStyles | TemplateStyles ]].
TemplateStyles will store CSS in templates on a separate page.
This way, styles in stylesheets can be referred to by several templates. Small templates are not styled well for mobile, which is a problem given the number of readers who come from mobile. This will make it easier to have different styles for mobile and desktop. We should also have an ongoing conversation with the communities as to what can, within reason, be done with style sheets. Is there anything they'd like to do that can't that we could do with this?
Reading wants CL support for this. Template editors should be aware of what's happening and understand why we consider it important, our templates have mobile-friendly styles (not necessarily the same as for desktop), and template editors should know how to do different styles for desktop and mobile, which we should make as easy as possible for them.
As the feature is deployed we work with communities to build awareness and contributors feel empowered to use the feature to improve the readability of content.
As suggested in T164927#3726517,
"Assuming everything goes as anticipated, to build awareness, I'll post announcements to the appropriate talk pages (Village Pumps) and mailing lists to let contributors know of the new feature, reference documentation, and let folks know where to get help.
Additionally, it's recommended that as we work with the communities to enable this feature we use something like a notice on the Template namespace ([[ https://en.wikipedia.org/wiki/Template:Editnotices/Namespace/Template | English Wikipedia example ]]) for a few weeks after enabling the feature to let logged-in contributors know of the feature - in case they miss the initial announcement. This is something I'm happy to help draft, but when possible would love to have community support for enabling."
 (for communities we approach in the initial phase) Post announcement of the feature
 Receive any feedback and address questions
 Update documentation if necessary
 Optional, but strongly encouraged, post "in-workflow" reminders of the features with community assistance for a few weeks after enabling the feature
No specific timeline. Could continue through the WMF fiscal year of 2017/2018, but the sooner the better.