The parent project, NodeGUI, has some Windows screenshots and examples – I’m not familiar enough with Fluent or WinUI, but basically the UI runtime is Qt5, so integrating it into genuine Windows apps is out of scope (but may well be possible with the right expertise). I assume it would involve some kind of Qt-hosting view. I’m unsure whether Qt5 can host Windows UI components.

Edit: NodeGUI here: https://github.com/nodegui/nodegui

WinUI 3 improves the ability to embed fluent UI “xaml islands” in Win32 apps (like Qt processes) but it’s extremely convoluted and requires a lot of boilerplate (that I believe Qt could theoretically abstract over being at a high-enough level).

> I’m unsure whether Qt5 can host Windows UI components.

yep, basically you have to do :

    auto window = QWindow::fromWinId(reinterpret_cast<WId>(/* HWND, NSView, X11 buffer, Wayland surface... /*));
    auto widget = QWidget::createWindowContainer(window);

and then you can use the widget like any other Qt widget, put it in a layout, etc... (of course caveats may apply when you start doing transparency or other fun things).