You will need to install a user script manager extension to install this script.
You may also like Imgur - Minimal Design for non-Imgurians.
It's same new Twitter, except much cleaner and little bit better. 🐦
(See the screenshots at the bottom)
This userstyle can't remove everything because limitations of current CSS and complexity of layout.
So I also made uBlock filterlist that removes even more elements, that are harder to do otherwise.
This userstyle and filterlist works ONLY with English language (I'm not adding support for other languages).
Works best with default white theme, but other themes are supported for element blocks.
Optional userstyles, made by me.
Optional userscripts by other developers, that in my option makes Twitter so much better again.