[steve1977]

Classic style actually worked up to and including Windows 7:

https://betawiki.net/images/d/da/Windows_7_classic_theme.png

[trealira]

Thanks for letting me know. I looked into it, and apparently it's still even possible to activate on later versions of Windows with registry edits and helper software: https://github.com/valinet/ExplorerPatcher/discussions/167