PrimeVue uses the system as the default darkModeSelector in theme configuration. If you have a dark mode switch in your application, set the darkModeSelector to the selector you utilize such as .my-app-dark so that PrimeVue can fit in seamlessly with your color scheme.
Following is a very basic example implementation of a dark mode switch, you may extend it further by involving prefers-color-scheme to retrieve it from the system initially and use localStorage to make it stateful. See this article for more information.
In case you prefer to use dark mode all the time, apply the darkModeSelector initially and never change it.
It is also possible to disable dark mode completely using false or none as the value of the selector.