We would like to give users the ability to collapse the sidebar. We believe this will lead to a cleaner reading and editing experience while continuing to give access to important functionality.
== Acceptance criteria
 Collapsed sidebar - sidebar will collapse when selecting the button adjacent to the logo
 Limit content width (parser-output). Strictly no changes to target content that is larger than this content width. That will be worked on later. (No responsive CSS for content at this point)
 Sidebar will be open by default for all users (with the possibility to close by default for logged-out users at a later time)
 State of the sidebar is preserved for logged-in users across sessions (nice to have: globally)
 Sidebar should be sticky, independent of the content
== Sidebar behavior
(Initial) logged-out - sidebar open, persistent throughout session
(Eventual) logged-out - sidebar closed, persistent throughout session
Logged-in - acts as a preference, persistent across sessions (nice to have, globally)
http://patchdemo.wmflabs.org/wikis/360edc1b162a277dd4f1f121023c7864/w/ (Code: [[ https://github.com/DemianX0/mediawiki-skins-Vector/commits/new-vector-header | GitHub - detailed ]] | [[ https://gerrit.wikimedia.org/r/c/mediawiki/skins/Vector/+/578994/3 | Gerrit - squash ]])
== Metrics (qualitative and quantitative)
 Do people discover that the sidebar is collapsible?
 Do people collapse it and leave it collapsed?
 Is there any effects on account creation?
 Is there any effect on donations?
- kowiki gadget