[mhd]

There are some OS 9 ("Platinum") GTK themes, but AFAIK there's no clone of the classic finder available. Nor other parts of the default OS 8/9 desktop.

Which is quite interesting, considering that the classic Finder is often thought as the pinnacle of spatial navigation. And Linux does have more obscure file managers cloned, like Amiga's Dopus[1] or the RiscOS one[2].

[1]: http://www.boomerangsworld.de/cms/worker/

[2]: http://rox.sourceforge.net/desktop/

[alxlaz]

Worth a warning: the recent history of GTK theming is pretty tortuous, and the GTK3 theming engine, while extremely flexible, doesn't really lend itself to non-modern (I can't think of a better euphemism) designs.

There are some themes, like Memphis98, that sort manage to create the sort of visual appearance that you're after. However, the GTK 3-ness is obvious even there: the "Open file..." dialog has huge, unresizable widgets on the left, combo bars are long. Lots of UI elements are bulky and oversized.

Consequently, in my experience, you're actually better off with a GTK2 theme and Qt applications with the gtk2 style engine.

I'm not really a fan of old-time themes -- I mean, I miss my Amiga but not that much. I know about this stuff for altogether different reasons -- I spent a lot of time trying to get a more compact layout, because GTK3 applications are pretty much unusable on small/low-density/low-resolution screens (and, IMHO, way too large even on "normal"-ish screens. I have a 27" monitor and, at 2560x1440, everything is so big it drives me nuts). I even tried to write my own, and failed pretty badly. So yeah.

[mhd]

Never mind that the biggest part of the classic finder experience wasn't the look-and-feel, so just a theme won't help you much.

And speaking of modern screens, even if you get a copy of the OS 9 font (Chicago?), it would look quite odd on high resolution, especially if it's anti-aliased.

And I definitely agree about the weird issues we've got with screen sizes today. I rarely get something in the "goldilocks" zone, either it's all Material/Aero with yuge margins and white space that would make Jan Tschichold blush, or its old UIs that are just a bit too small (try running the aforementioned Worker file manager on a HiDPi screen).

[philwelch]

Mac OS 8 migrated from Chicago to Charcoal, I think. Chicago was resurrected as the UI font on the first iPods because it was a similar situation as the original Macintosh that Chicago was designed for (low-res monochrome screens).

[WorldMaker]

Gnome's own Nautilus had direct support for spatial navigation for a long time in the Gnome 2 era (including briefly on by default in something like Gnome 2.6 before complaints reversed that decision), though it was obviously a small bit underwhelming compared to Mac Classic, and lost entirely in the Gnome 2 to 3 transition.

https://people.gnome.org/~bmsmith/build/nautilus-spatial-mod...

http://www.bytebot.net/geekdocs/spatial-nautilus.html