Recently, Qt has decided that they will offer their open-sourced libraries only if you have a Qt account. Furthermore their LTS versions are officially behind a paywall.
[https://www.qt.io/blog/qt-offering-changes-2020](https://www.qt.io/blog/qt-offering-changes-2020) I hope to start using the Nuklear binding soon. I am familiar with Gtk myself, but there isn't any uptodate gtk3 bindings as far as I am concerned.