To apply a userChrome or userContent css file in TB 68, you should toggle the preference toolkit.legacyUserProfileCustomizations.stylesheets to true in Edit/Preferences/Advanced/General/Config. editor.

There are plenty of userChrome examples:

http://www.linnhe2.free-online.co.uk/thunderbird/chrome.html

https://gist.github.com/AnthonyDiGirolamo/6032387

Thanks for replying.

I changed legacyUserProfileCustomizations.stylesheets to true, but Thunderbird is still ignoring my userChrome.css.

userChrome.css is located in my home directory under .thunderbird/*.default/chrome.

Here is the userChrome.css I've been trying to get to work:

* Do not remove the @namespace line -- it's required for correct functioning
*/

@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"); /* set default namespace to XUL */ /*

* Make all the default font sizes 20 pt:
*/

• {

 font-size: 14pt !important;
 font-family: Verdana !important;

} /* change font size of menu items */ menupopup > *, popup > * {

 font-size: 18pt !important;

} /* change font size of menu items */ menubar > menu * {

 font-size: 18pt !important;

}

Is there a way to look at the log?

Here is a similar file I pieced together from various sources. Tested and working in TB 68.2.2.

@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");

/* Menu Bar font */
menubar > menu
{ font-size: 18pt !important;
}

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

/* Folder Pane font */
#folderTree > treechildren {
  font-size: 12pt !important;
  font-family: Verdana !important;
}

/*  Threads Pane font */
.tree-rows {
    font-size: 12pt !important;
    font-family: Verdana !important;
}

I think the last section will also work for the Folder Pane, if the previous section is omitted. The last declaration overrides any previous ones.

Thanks for trying, but it still isn't working.

I changed my userChrome.css file to the one you supplied but changed the fonts to huge and it hasn't changed anything.

Any idea where to go from here?

Are you sure the userChrome.css file is in the chrome folder, which must be a subfolder of the active profile folder? Help/Troubleshooting Information, click Open Folder to open the active profile folder. You may have more than one profile folder, even if only one is used, after updating to TB 68. I can't think of any reason why the script would work in W10 but not in Linux.

I just checked the profile folder as you suggested and browsed directly to userChrome.css.

The file is in the right place.

I found some legacy add ons, including one of the font changers. I disabled it. That didn't help either.

ExQuilla won't go away though. It says it will be uninstalled when I restart thunderbird, but restarting doesn't seem to be working. I wonder if there is a residual thread preventing that from working. Let me look...

That was it. There was a dead thunderbird thread hanging around and preventing the css file from being read. I killed it and now the fonts have changed. Now I need to get the preview pane to have a bigger font.

Thanks much for your help.

Okay. Let me continue.

I made the mistake of trying a dark mode theme on Plasma.

Thunderbird copied it and now I can't get the preview pane to switch back to light mode. I'm guessing I need to reboot. The biggest issue is the I bar is teeny and RED so I can't see it on the dark background. I switched back to light mode using the settings in Thunderbird, but the preview pane is still in dark mode.

Also, the font in the preview pane is too small. What's the css voodoo to increase it?

You guys really need to design a plugin or just add these features to Thunderbird. Changing the look and feel is important and how it's done for thunderbird sets a high bar for average users, a bar they'll refuse to jump.

Fonts for the Message Pane (preview pane) are best adjusted through Edit/Preferences/Display/Formatting/Fonts & Colors/Advanced... Set the fonts and sizes with Fonts for:Latin and repeat with Fonts for:Other Writing Systems. Uncheck 'Allow messages to use other fonts'.

Another method using userContent.css:

http://forums.mozillazine.org/viewtopic.php?p=14767124&sid=f96452d1c0bb60eaef05ad7a9289015a#p14767124

Thanks!

That worked for the fonts. Now I just gotta get rid of dark mode in the preview pane.

The background color, at least for plain text messages, can be set under .../Display/Formatting/Fonts & Colors/Colors... You may have to adjust the override setting.

Unchecking "Use System Colors" fixed it.

It looks like it doesn't detect system color changes.

The weird thing is: I went back to try to check it again to see if it would update to system colors and I can't check the box at all now.

But, it's working for now.

I really appreciate you taking the time to help me out. Thanks so much!

I just installed 68.3.1 (32-bit) on a fresh OEM WinX and the fonts on the preview pane are a literal pain because they are like 8 points and won't respond to any changes I make in the Options/Display/Formatting menu. I can run that sucker up to size 48 and it makes NO difference in what I see.

HELP!

Anan,

Please look at the above css files and their locations. That is the best way to adjust font sizes in thunderbird.

Anan said

I just installed 68.3.1 (32-bit) on a fresh OEM WinX and the fonts on the preview pane are a literal pain because they are like 8 points and won't respond to any changes I make in the Options/Display/Formatting menu. I can run that sucker up to size 48 and it makes NO difference in what I see. HELP!

If you want to adjust the fonts for the Threads and Folder Panes in your picture, there is a way using css files:

https://support.mozilla.org/en-US/questions/1272749#answer-1266095

Adjusting the fonts in received or composed messages requires a different method.

A simple way to increase the fonts for everything is explained here:

https://support.mozilla.org/en-US/questions/1269361#answer-1256755