Tailwind works for npm run build && npm run preview aswellas npm run dev but tailwind styles don't apply on github pages.
astro.config.mjs:
import { defineConfig } from 'astro/config';
import tailwind from "@astrojs/tailwind";
// https://astro.build/config
export default defineConfig({
integrations: [tailwind()],
site: 'https://onrirr.github.io',
base: '/astro-portfolio',
});