[ptx]

Ah, perhaps I should have said "styles" rather than "themes"! I was thinking of the look-and-feel of the widgets, not the colors and window decorations. The widgets in all those screenshots seem to use Qt's Windows style.

Here's an example of the Motif style in KDE 1: https://commons.wikimedia.org/wiki/Category:Screenshots_of_K...

KDE 2 introduced customizable styles for the widgets, I'm pretty sure, e.g. this somewhat gaudy one: https://commons.wikimedia.org/wiki/Category:Screenshots_of_K...

...or this BeOS-inspired one: https://timeline.kde.org/images/kde2b3_6.png

The release notes for 2.0 [1] say:

> KDE's sophisticated theme support starts with Qt's style engine, which permits developers and artists to create their own widget designs. KDE 2.0 ships with over 14 of these styles, some of which emulate the look of various operating systems, and additionally does an excellent job of importing themes from GTK and GNOME.

[1] https://kde.org/announcements/1-2-3/2.0/