php storm hundreds of errors in app.css

hi everything has been fine until today, my app.css file in the public/filament folder has hundreds of errors showing, do you known why this could be?

Cannot resolve '--gray-200' custom property
Cannot resolve '--gray-400' custom property
Cannot resolve '--gray-400' custom property

very weird as vscode does not have these errors, and there are no errors building, launching and running npm run dev. Hope you can help thanks