Dark mode is reported to increase MRR by over 300% and reduce churn to 0%.
Just kidding.
However, you probably still want to add dark mode to your app to avoid blinding users at night.
I wrote a tutorial on how to add dark mode to a React app, or if that's too much work - Gravity now ships with dark mode included.
https://usegravity.app/blog/how-to-add-dark-mode-to-a-react-app