> Classic Macs OS 8.5~9 [...] Aqua?
Aqua is (was†) Mac OS X, Mac OS 8~9 was Platinum.
† While the current design continues to be called "Aqua" I personally consider the last iteration of Aqua to be Mavericks. While Cheetah, Puma, and Jaguar had the filling lines, Panther and Tiger had brushed metal, and the brief touchdown with skeuomorphism in Lion and Mountain Lion, they overall consistently carried the colourful glossy-watery "lick-it-candy" theme throughout - including icons - all the way, until Yosemite happens... Then it gets all silky with frosted glass, desaturated colours, and muted gradients, which just does not have the Aqua feel to me.
https://www.mailvita.com/kb/list-of-all-versions-of-mac-os-f...