I'm trying to install Tailwind on my React project.
I followed the instructions on https://tailwindcss.com/docs/guides/create-react-app and I'm using Windows10.
I tried to apply the color but it's not working.
My guess is that the codes below for index.css is wrong.
I get this orange wavy line under @tailwind and when I hover it, it says "Unknown rules @ tailwind".
I appreciate if anyone can help with this issue.

@tailwind base;
@tailwind components;
@tailwind utilities;

Here are my codes.

package.json

{
  "name": "react-project",
  "version": "0.1.0",
  "private": true,
  "dependencies": {
    "@testing-library/jest-dom": "^5.16.5",
    "@testing-library/react": "^13.3.0",
    "@testing-library/user-event": "^13.5.0",
    "react": "^18.2.0",
    "react-dom": "^18.2.0",
    "react-scripts": "5.0.1",
    "uuid": "^8.3.2",
    "web-vitals": "^2.1.4"
  },
  "scripts": {
    "start": "react-scripts start",
    "build": "react-scripts build",
    "test": "react-scripts test",
    "eject": "react-scripts eject"
  },
  "eslintConfig": {
    "extends": [
      "react-app",
      "react-app/jest"
    ]
  },
  "browserslist": {
    "production": [
      ">0.2%",
      "not dead",
      "not op_mini all"
    ],
    "development": [
      "last 1 chrome version",
      "last 1 firefox version",
      "last 1 safari version"
    ]
  },
  "devDependencies": {
    "autoprefixer": "^10.4.8",
    "postcss": "^8.4.16",
    "tailwindcss": "^3.1.8"
  }
}

index.css

@tailwind base;
@tailwind components;
@tailwind utilities;

postcss.config.js

module.exports = {
  plugins: {
    tailwindcss: {},
    autoprefixer: {},
  },
}

tailwind.config.js

/** @type {import('tailwindcss').Config} */
module.exports = {
  content: [
    "./src/**/*.{js,jsx,ts,tsx}",
  ],
  theme: {
    extend: {},
  },
  plugins: [],
}

App.js

return (
  

    

      Hello!
    
  

Thank you!

Screenshot added after posted.