Installing Tailwind to Astro or Vite

Install with your package manager:

npm install -D tailwind @tailwindcss/vite

Add to your astro.config.mjs:

import { defineConfig } from "astro/config";
import tailwindcss from "@tailwindcss/vite";

// https://astro.build/config
export default defineConfig({
  vite: {
    plugins: [tailwindcss()],
  },
});

See Install Tailwind CSS with Astro - Tailwind CSS