changing display font size in Thunderbird

It continues to seem odd to be discussing Thunderbird on a Mulberry 
list, but I continue to believe that Thunderbird is the most likely 
successor to Mulberry for me, and I'm trying to learn about it.

I have finally succeeded in changing the font size in message list displays:

* Find the Mozilla profile folder (on my Mac it's in 
~/Library/Thunderbird/Profiles
* create in it a subfolder named "chrome"
* create chrome/userChrome.css if it doesn't already exist
* Add this css entry:

/* Global UI font */
* { font-size: 11pt;
   font-family: Lucida;
}

I can now read my Thunderbird inbox listing without my glasses. Hooray.