saurav7747/ChatLord ? reverse-engineered prompt

Build me a fast private chat app that feels like WhatsApp, but as a PWA that people can install on their phone or desktop.

It should let users sign in, see their chats, open a conversation, send messages, and switch between contacts and group chats. I want a clean dark first design with a light mode option, plus a nice install prompt and basic offline support so the app still opens when the connection is weak. It should connect to my existing Supabase project for login, chat data, storage, and live updates, and it should respect the security rules already set up there.

Please keep it all in the frontend, use simple plain CSS, and make it easy to run and deploy as a static site. If you need to check current docs for Supabase or PWA behavior, go ahead and look them up online.