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Is there a way to change the tabs' font to BOLD?

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  • 1 has this problem
  • 33 views
  • Last reply by tigerdg

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This question was asked a few months ago and is archived now. It gave a detailed explanation of how to make the tab text bold. I followed the instructions carefully, but it did not work. Maybe this method doesn't work in the current version of Firefox (77.0.1 as of this writing)? The solution involved adding to or creating a userChrome.css file, which I did (the answer also referenced the filename "userContent.css", which I also tried without success).

The solution said to create a css file that contained this text:

#TabsToolbar .tabbrowser-tab .tab-content {
  font-weight: 800 !important;
}

put it in a folder named "chrome" in the user profile folder, and then restart Firefox, which I did, but it had no effect.

Anyone have another solution, perhaps that works with a later version of Firefox? Thanks much.

This question was asked a few months ago and is archived now. It gave a detailed explanation of how to make the tab text bold. I followed the instructions carefully, but it did not work. Maybe this method doesn't work in the current version of Firefox (77.0.1 as of this writing)? The solution involved adding to or creating a userChrome.css file, which I did (the answer also referenced the filename "userContent.css", which I also tried without success). The solution said to create a css file that contained this text: <pre><nowiki>#TabsToolbar .tabbrowser-tab .tab-content { font-weight: 800 !important; } </nowiki></pre> put it in a folder named "chrome" in the user profile folder, and then restart Firefox, which I did, but it had no effect. Anyone have another solution, perhaps that works with a later version of Firefox? Thanks much.

Modified by cor-el

Chosen solution

It is not that difficult to create userChrome.css if you have never used it.

The first step is to open the "Help -> Troubleshooting Information" page and find the button to access the profile folder.

You can find this button under the "Application Basics" section as "Profile Folder -> Open Folder".
If you click this button then you open the profile folder in the Windows File Explorer.
You need to create a folder with the name chrome in this folder (name is all lowercase).
In the chrome folder you need to create a plain text file with the name userChrome.css (name is case sensitive).
In this userChrome.css text file you paste the text posted.

In Windows saving the file is usually the only time things get more complicated because Windows can silently add a .txt file extension and you end up with a file named userChrome.css.txt.
To avoid this you need to make sure to select "All files" in the dialog to save the file in the text editor using "Save File as".

You need to close (Quit/Exit) and restart Firefox when you create or modify the userChrome.css file.

See also:

In Firefox 69 and later you need to set this pref to true on the about:config page to enable userChrome.css and userContent.css in the chrome folder.

  • toolkit.legacyUserProfileCustomizations.stylesheets = true

See:

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Chosen Solution

It is not that difficult to create userChrome.css if you have never used it.

The first step is to open the "Help -> Troubleshooting Information" page and find the button to access the profile folder.

You can find this button under the "Application Basics" section as "Profile Folder -> Open Folder".
If you click this button then you open the profile folder in the Windows File Explorer.
You need to create a folder with the name chrome in this folder (name is all lowercase).
In the chrome folder you need to create a plain text file with the name userChrome.css (name is case sensitive).
In this userChrome.css text file you paste the text posted.

In Windows saving the file is usually the only time things get more complicated because Windows can silently add a .txt file extension and you end up with a file named userChrome.css.txt.
To avoid this you need to make sure to select "All files" in the dialog to save the file in the text editor using "Save File as".

You need to close (Quit/Exit) and restart Firefox when you create or modify the userChrome.css file.

See also:

In Firefox 69 and later you need to set this pref to true on the about:config page to enable userChrome.css and userContent.css in the chrome folder.

  • toolkit.legacyUserProfileCustomizations.stylesheets = true

See:

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That rule still works in Firefox 77, but on Windows, with the default font Segoe UI, it looks really bizarre to me (see attached). Possibly a rule that selects a nicer font would help (I didn't try it).

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tigerdg said

... The solution involved adding to or creating a userChrome.css file, which I did (the answer also referenced the filename "userContent.css", which I also tried without success). ...

userChrome.css is what you need for modifying the Firefox UI (User Interface).

userContent.css is for page content mostly. To affect web pages that are displayed in the content area of the browser window. ... But there could be some 'overlap' where both work in conjunction with each other, can't provide any examples now as I stopped using then with each other with Quantum Firefox 57 and later. I barely understand how each works by themselves, and a real stretch when used with each other since the days of Legacy extensions ended.

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I had done everything right, but did no know that I had to turn that toolkit legacy customization switch to "true." That was not in the original solution, most likely because at that time, it wasn't necessary. Thanks much for solving my problem!