useDarkTheme.js is our custom hook to import where it is needed.

App.js is (in this case) our target.

App.css in body we declare our colors as variable (to make things more scalable), adding our custom .dark-mode class with accent colors when switching to dark mode .

Runs the app in the development mode.
Open http://localhost:3000 to view it in the browser.

The page will reload if you make edits.
You will also see any lint errors in the console.