react.js & tailwind.css project not deploying to heroku properly - reactjs

Question

I have a create-react-app that I have successfully gotten up and running on my localhost, with all of the features of tailwind.css available for me to integrate with my JSX. It compiles fine and I used this tutorial to accomplish this: https://codingthesmartway.com/using-tailwind-css-with-react/.
An example of an error, commas representing new console log lines, is: npm ERR! react-tailwindcss#0.1.0 build:css: postcss src/styles/tailwind.css -o src/styles/main.css, npm ERR! spawn ENOENT, npm ERR!, npm ERR! Failed at the react-tailwindcss#0.1.0 build:css script. I used heroku logs --tail to get this information. I am at a loss as to how to fix this issue. This is the app: https://peaceful-island-18911.herokuapp.com/. It should look like (and does on my localhost) the end result of the tutorial mentioned. I know there has to be a way to get a react w/ tailwindcss app deployed to heroku and function as it does on localhost. I have done it before using the more common css framework bootstrap.
Below is my package.json file with my scripts and dependencies. I followed the tutorial I mentioned above for my file architecture. I am a newer dev so please go easy on me but any help or guidance in solving this issue will be greatly appreciated. I really hope this is a simple fix beginner mistake! Thank you.
{
"name": "react-tailwindcss",
"version": "0.1.0",
"private": true,
"dependencies": {
"#testing-library/jest-dom": "^4.2.4",
"#testing-library/react": "^9.5.0",
"#testing-library/user-event": "^7.2.1",
"react": "^16.13.1",
"react-dom": "^16.13.1",
"react-scripts": "3.4.1"
},
"scripts": {
"start": "npm run build:css && react-scripts start",
"build": "npm run build:css && react-scripts build",
"test": "react-scripts test",
"eject": "react-scripts eject",
"build:css": "postcss src/styles/tailwind.css -o src/styles/main.css",
"prebuild": "npm run build:css",
"prestart": "npm run build:css"
},
"eslintConfig": {
"extends": "react-app"
},
"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": "^9.8.6",
"postcss-cli": "^7.1.1",
"tailwindcss": "^1.6.2"
}
}