Font and density settings are found in ☰

Font only changes the font size, not the font, which is my problem. As discussed in another thread, Density just adds line spacing, but doesn't change the font spacing.

Threads pane font css:

table[is="tree-view-table"]{
background: #87CEFA !important;
font-family: Times, serif !important;
font-size: 16px !important;
color: navy !important;
}

Help/Troubleshooting Info, Profile Folder, Open Folder, close TB, create a new folder named chrome, create a new document in chrome with a text editor, name it userChrome.css, Save as type: All files *.*, copy in the above code, change the numbers, family and colours as desired. Double-click toolkit.legacyUserProfileCustomizations.stylesheets to true in Settings/General/Config. editor, restart TB.

Online css generator

That doesn't work on 115.3.2, I just got this update with an horrible font, my userchrome.css was still there, the toolkit.legacyUserProfileCustomizations.stylesheets was still on "true" from previous versions I've pasted your code which was slightly different from the one I had but no change, still get that illisible font.

I had forgotten to save the updated userchrome.css so the top bar still had my previous font but your code reverted the top bar to the horrible 115 font and did not change the left pane font

I had forgotten to save the updated userchrome.css so the top bar still had my previous font but your code reverted the top bar to the horrible 115 font and did not change the left pane font

The code in this topic is for the Threads Pane. For the Folder Pane, see this topic:

https://support.mozilla.org/en-US/questions/1427253

Thanks ! both work now, don't know why the message list code showed here didn't work until I put the 2 codes from the link you gave even though the message list code is the same as on this page.

The threads pane is what you call the message list pane.

The code works, so I suggest you review all the steps to apply the code. There are several pitfalls.

https://www.askvg.com/tip-how-to-move-menu-bar-at-top-in-mozilla-thunderbird/

OK. The message list pane is the name given by Mozilla as you can see on the picture attached from Mozilla.

Now the menu bar and status bar have that ugly default font, how can I change it aswell ? thanks

PS and the header bar aswell

In fact that annoying font is everywhere, all the dialogs, boxes, the options don't change it, how to completely replace it  ?

To change the Menu Bar font:

/* Menu Bar font */
menubar > menu
{ font-size: 14px !important;
font-weight: bold !important;
font-family: Times, serif !important;
}

To change the submenus and context menus:

/* Submenus and context menus font */
menupopup, popup {
    font-size: 12pt !important;
    font-weight: bold !important;
    font-family: Times, serif !important;
}

To change the global UI font:

/* global font */
* { 
	font-size: 10pt !important;
  	font-family: Cambria, serif !important;
	/*font-size: 12pt !important;
  	font-family: Open Sans, sans-serif !important; */
} 

thanks so much sfhowes !!

I set the density to compact and this looks nice on my screen:

/* global font */

• {

font-family: Arial !important; font-size: 9pt !important; line-height: 2 !important; }

If anyone wants to play, Mozilla.org has a full list of css codes.

Tried fixing fonts on Windows 11, TBird version 115.3.3. I'm handicapped by being unsure of the terms for various portions of the TBird interface, plus almost zero CSS experience.

I've got the chrome sub-folder in the Thunderbird Email folder. I've got the userChrome.css file in the chrome folder. Its contents follow. This after trying several iterations, cut-and-paste the font stuff from various sources.

Here is what my Tbird looks like: https://www.arkacy.com/Other/Temp-Upl.../A

So, the "Menu Bar" stuff works, but nothing else. What's the CSS code for the Index and the Email list?

/* Menu Bar font */ menubar > menu { font-size: 20px !important; font-weight: normal !important; font-family: "Times New Roman", Times, serif !important; } To change the submenus and context menus:

/* Submenus and context menus font */ menupopup, popup {

   font-size: 12pt !important;
   font-weight: normal !important;
   font-family: "Times New Roman", Times, serif !important;

}

To change the global UI font:

/* global font */

• {

font-size: 10pt !important;

 	font-family: "Times New Roman", Times, serif !important;

font-size: 12pt !important;

       font-weight: normal !important;
 	font-family: Open Sans, sans-serif !important;

}

The only thing you need in your userChrome.css file is:

/* global font */

• {

font-family: Arial !important; font-size: 9pt !important; line-height: 2 !important; }

This will make everything 9pt Arial.

Panache - Thanks, but still no joy. The "Menu Bar" code works, but nothing else. Even the submenus and popup codes don't work. The global font code does not change anything.

Again, I don't know CSS, but I'm an old coder (Cobol, Fortran, etc.). I see that the Menu Bar code contains the line "menubar > menu". That's some kind of tag, I guess? The global font code contains no such line. Should it?

Is there any documentation anywhere on what those "tags" are for Thunderbird? Any docs describing what the various elements of the Thunderbird interface are called?

Tried fixing fonts on Windows 11, TBird version 115.3.3. I'm handicapped by being unsure of the terms for various portions of the TBird interface, plus almost zero CSS experience. I've got the chrome sub-folder in the Thunderbird Email folder. I've got the userChrome.css file in the chrome folder. Its contents follow. This after trying several iterations, cut-and-paste the font stuff from various sources. Here is what my Tbird looks like: https://www.arkacy.com/Other/Temp-Upl.../A

To change the fonts for the Folder Pane (folder index) and Threads Pane (email list), see this topic:

https://support.mozilla.org/en-US/questions/1427253

sfhowes - Bingo, that's the ticket. Just take out the ugly colors and it looks great. Thanks.