Install Diesel and Watchexec:

sudo pacman -S diesel-cli watchexec

Absolutely use pnpm as packet manager for this project.

To run the Tailwind Compiler in watch:

pnpm dlx @tailwindcss/cli -i styles/tailwind.css -o assets/generated/main.css --watch

or (with or without --watch)

pnpm compile

My suggestion is to open one terminal and run pnpm devrun to continously rebuild the Tailwind css and restart/rebuild the Rust server if a template file change.