Greasy Fork is available in English.
Hides most of the random, unrelated videos which YouTube injects into search results, but still allows you to access them. This script gathers videos from categories like "People also watched" and "For you" and collapses them into thin boxes on-screen so they won't distract from actual search results. Hover the mouse over these boxes to show their contents.
< Feedback on YouTube - Search Results Cleaner
In what way doesn't it work? What did you change? Also, I wrote a stylesheet, not a userscript. What your using (and what you posted) is an automatic conversion by Greasyfork; it's not what I wrote.
Oh, well, I did not know greasyfork generates those.
It does not work at all due to some syntax issues, but they are specific to the generated userscript.
My guess is something changed in how they are generated, which does not mesh that well with the usage of @-moz-document.
The userscript version of your user style is currently not working.
I am very inexperienced with JS and CSS, but I tried to fix it and was successful at it.
I have the fixed version in a gist in case you want to check it.
https://gist.github.com/Katzenwerfer/d6f6bdfbf8d504a9309c6c809f3b3124