i tuned the #Thunderbird #CSS a bit for when using dark mode and the Dark Reader extension..

..userContent.css normalizes text and blockquotes for plain text, sets message body width to 80 characters, etc.
https://git.sr.ht/~e33io/dotfiles/tree/master/item/misc/Thunderbird/chrome/userContent.css

..userChrome.css fixes info bar warnings, unselected UI tabs, calendar sidebars, etc.
https://git.sr.ht/~e33io/dotfiles/tree/master/item/misc/Thunderbird/chrome/userChrome.css