How to change the font-size of Thunderbird thread list on a Mac?

Question

How to change the font-size of Thunderbird thread list on a Mac?

I don't see any settings in the preferences.

Answer 1

Does command + scroll wheel do anything?

Answer 2

You need to edit your userChrome.css.

Go to ~/Library/Thunderbird/Profiles/[yourProfileName]/chrome/ (creating the chrome directory if it doesn't exist) and edit userChrome.css, again creating if it doesn't exist.

For example, to edit all text in Thunderbird (except message view), enter the following:

/* Global UI font */
* { font-size: 18pt !important;
  font-family: Verdana !important; 
} 

The result looks something like this:

Unfortunately, I was unable to find the CSS class for the message list. Replace the * in the css with that css class and it should work as intended.