@ FluxApex,
Thanks, I had forgotten to make the chrome directory, indeed.
So I made it and took the userChrome.css file there (into the Chrome directory). . . But it doensn't work.
I use Linux not Windows, so the right path for my Chrome directory is:
/home/"user-name"/.mozilla/firefox/"name_of_profile_directory".default/Chrome/userChrome.css
I don't know where is the problem, but I will try to investigate it.
Maybe the name of the "Chrome" directory have to change to "chrome", because Linux is sensitive for letters and makes diference between capitals and non-capitals.
On the other hand, you are right, I make a redundancy in my userChrome.css so I made a correction for this reason.
Thanks again.
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Update:
I made a directory in my profile directory of Firefox named "chrome", too. I copied the userChrome.css file to that.
So I have to directories with this css file, one named "Chrome" and another named "chrome". Nothing happened after restarting of Firefox (version 58.0.2 , 64bit on Linux Mint 18.3 Xfce) .
What could be the root of this issue ?
