In my Angular 19 project with tailwind 4 and project hierarchy:

• root
  • backend/..
  • frontend/webapp

I had to add to ".vscode\settings.json":

"tailwindCSS.experimental.configFile": "frontend/webapp/src/styles.scss"

And the restart vscode - then it finally started working.

The "tailwind.config.js" is actually not needed anymore.

Follow this guide to setup tailwind in Angular:

https://tailwindcss.com/docs/installation/framework-guides/angular