Try to use hero ui beta version. I use "@heroui/react": "^2.8.0-beta.8".

Set main css like in documentation of TW4 in HeroUI (https://www.heroui.com/docs/guide/tailwind-v4),

but call node_modules first, then @plugin hero.ts.

=>app/globals.css

```css

@import 'tailwindcss';

@source '../../node_modules/@heroui/theme/dist/**/*.{js,ts,jsx,tsx}';

@custom-variant dark (&:is(.dark *));

@plugin './hero.ts';

```

It works for my project.