Thunderbird with Fluent design principles & Mica materials
So, I've been wanting to ditch Outlook classic for some time. Outdated HTML rendering engine, Copilot buttons fored down your throat at every turn, and, more importantly, end of life looming, and "New Outlook" lacks the power user features I need.
Realistically, Thunderbird is the only alternative. However, and I mean this as nicely as possible.... it's a bit ugly. At least, out of the box.
I've seen many threads asking for Mica support, or commenting on the design. The answer is, surprisingly, Thunderbird already supports Mica using the exact same advanced config flags as FireFox.
Enter userChrome.css. I've modified the UI to follow Fluent deisgn principles, the freely available Fluent icon sets, and redesigned the window layout to better suit Fluent / Mica.
The end result is a mail client that looks right at home on Windows 11 :)
And a nicer, floating tab design;
I intend to release this on GitHub once it is completed. I need to give the various other sections the same treatment (only Mail is done currently) and tidy a few more bits up. But curious to know if there would be any interest in people having this available.
Posted Jul 5, 2025, 11:52 AM UTC