The application needs icons that match the elementary OS icon style guidelines.

I was thinking that the internet browser icon can be adapted since it is basically the Yin-Yang symbol.

We also need two wingpanel "symbolic" versions of the icon. One should denote light mode and one should denote dark mode. The symbolic icons are typically black and white. Here are some current examples.

Any designs or help would be appreciated!

Thanks for your submission to AppCenter! I regret to inform you that we won't be publishing your app to AppCenter at this time. This is because your app seeks to modify other apps. While this is technically possible at the moment, in the near feature apps will become sandboxed via Flatpak and it will no longer be possible for apps to modify each other. In general, we believe this is a better security model, so we're enforcing it through AppCenter policy. Sorry to have to deliver bad news! I hope to see future app submissions from you for other kinds of apps :)

I can only comment on the screenshots but it looks like you need to enter the theme manually for the system. It would be nicer to add a dropdown so the users can choose the system theme.

Hey another nice feature would be an integration with Dark Reader Extension. This is one of the most used Extension when it comes to Webpage Darkmode and is also open source.
You can send calls to the extension if you expose a API and can trigger Dark Mode. This involves alot of work and knowledge but would achieve a truly universal Dark Mode.

DarkReader Repository

How can I install this? Thanks

I believe you already have plans of releasing to the AppCenter... but when? :D I just want some delicious updates.