True, but the original Steam was created for managing updates to Counter Strike and their anti-cheap system (VAC if memory serves me right). Also back when having a low WON ID (now SteamID) was a badge of honor (like having a low Slashdot account ID).

Sorry for the useless comment but I really like the idea of a „anti-cheap system“.

I will use it in my next presentation for shareholders. /s

I'm sure the behavioral economics people at Activision and EA trying to get kids to buy more cosmetics would have a lot to say about that...

Yes, the Steam client was originally built on top of the same VGUI library used in Valve's games, and used the same style as HL1/CS/etc back then.

Was VGUI built on GTK back then? It looked exactly the same as other GTK apps I was using in the early 00s.

Not sure - the VGUI code in the Half-Life SDK was a bunch of header files and a .lib file but I'm not sure what actually implemented it. Back in the early 2000s I assume it was either Windows-specific or rendered using DirectX/OpenGL.

It was added to Half-Life (and not long after to Counter-Strike) in March 2000 or so. Not sure when Steam first launched but I think there was a beta from 2002?

Yeah, still feels like even today Steam could pop up something in this style somewhere when you press a less common button or cause a less common error. Kind of like how Windows would occasionally have even Windows 3.x style dialogs up until last year in Windows 11, and still has a few stragglers from Windows 9x era.