Right now it looks like a Qt 3 application running in 2001.
Standard Dialogs Example: https://doc.qt.io/qt-5/qtwidgets-dialogs-standarddialogs-example.html
QMessageBox uses old macOS aqua looks http://doc.qt.io/qt-5/qmessagebox.html QTabWidget has some kind of win98 looks : http://doc.qt.io/qt-5/qtabwidget.html
- This page's screenshot is minuscule: http://doc.qt.io/qt-5/examples-layouts.html
Same here: http://doc.qt.io/qt-5/examples-qtassistant.html this one has no image: http://doc.qt.io/qt-5/qtassistant-remotecontrol-example.html ...and the link to the image at bottom is a 404 : Caused issue QTBUG-69821. Must be resolved there. this one has no image either : http://doc.qt.io/qt-5/qthelp-contextsensitivehelp-example.html this one has an image which looks fairly aliased : http://doc.qt.io/qt-5/qtdesigner-taskmenuextension-example.html
Frankly, looking at them all, it's all over the place ! shouldn't there be a CI automation script that would take the screenshots automatically on new qt releases ? Because that's what people will see when they use it.