The only 'advantage' GTK+ really has over Qt is that it's pure C, so there a lot more bindings for all the languages you're probably not going to use to write significant desktop software anyway.
Qt, wx* and Fltk (which are arguably the other most popular widgets in order of popularity) are all C++. Not to mention that wxWindows on linux actually uses GTK+ for rendering, and it uses a terrible event table mechanism.
The HN skin is actually a Chrome extension called Hacker News Extension Suite.
https://chrome.google.com/webstore/detail/hacker-news-enhanc...
Pretty much vanilla Elementary OS theme with Source Sans pro front.
Did write an article about Gtkmm for DDJ as part of it.
Eventually it stop making sense to me.
I am not sure what people want. At least buttons look like buttons (unlike the way iOS and other mobiles OSes are going). Is it a button? Is it a plane? No, it's text! You end up bashing your screen as it isn't obvious what to press. My mum is really confused.
Personally, I think XFCE looks nice out of the box (in Xubuntu, at least). And what's a better alternative? Unity and GNOME are both way too dumbed down for me, and KDE is both ugly (IMHO) and and quite buggy.
And another one: Xlib
hahaha lol
GTK+ was always incredibly poor in anything but linux, and with GTK3 the footprint/performance is worse than Qt.
wxWindows has a very ugly event table/dispatch mechanism, which somewhat reminds me of the old win32 api. On linux it even uses GTK+ for rendering. It used to make sense before Qt4 came, but nowdays I wouldn't use it.