For a Wide Screen and the YouTube new Design:
Player stay fixed at the LEFT side.
- Title on top video
- Videos related and in queue on the RIGHT side
- Infos, Comment on the RIGHT side ( visible on hover their tabs)
- Progress Bar is always visible
So, you can watch the video AND read infos / Comments (by hovering their tabs) without problem.
Userscripts support for:
"Agent switcher": Important Note:
After some problem with the use of an agent switcher, which broke this userstyle.
For use with Waterfox Classic and User-Agent Switcher by Alexander Schlarb, chose as settings:
- Force for the domain (the first one)
- Robot: Google Bot
Change in > v.10:
- Correction for support GM "YouTube: Age Verification Bypass: See Related videos panel right
- Support for more YouTube pages (Channels, Playlist, etc..., Youtube Music )
- Test for Embedded videos
- Auto Play Button Fixed on top right column (when not in the bottom video ).
- Add a "Live Chat" tab - near "Infos" and "Comments" tabs (use hover them to watch their contents) - in Video player page.
- Add counter for comments really loaded (we should wait their loading before seeing the comments tab too)
- Correction video player: center movie.
By example for horizontal center:
https://www.youtube.com/watch?v=DsyLuxfu64
and vertical center:
https://www.youtube.com/watch?v=yUif6CuJgk
- Support for no Dark mode.
It's a quick support , need more fine tuning, but i use always the Dark mode....
Gif Screenshot:
https://i.imgur.com/OiHhCS9.gif
Infos, Comments Tabs
https://i.imgur.com/a3ew4WP.gif
Chat tabs:
https://i.imgur.com/UblxArF.gif

It's Userstyle version, here:
Youtube WideScreen (New Design Polymer)
OR better on USO Archive (more fast and less buggy):
Youtube WideScreen (New Design Polymer)