Assegnate 5 su 5 stelle
Looks great on Thunderbird.59. It didn't work on 60.
Not complete though (chat is not changed) ...but nice.
This theme does style all of Thunderbird (and SeaMonkey) so if you're not seeing that then feel free to contact me, via the Support link on the right.
There is also a bug in Thunderbird version 60 itself that is affecting ALL Thunderbird themes - you often need to install a theme 2 or 3 times before it shows as it should! Maybe that is affecting you?