Some Tailwind styles not working in production with Next.js

Question

For some reason a few styles don't seem to be working in production build hosted on Netlify. This seems to only be happening on a single component. It's a wrapper located at ./layout/FormLayout.tsx (don't know if that changes anything). Here is the wrapper:

const FormLayout: React.FC<FormLayout> = ({ children, title, description }) => {
    return (
        <div className="w-screen mt-32 flex flex-col items-center justify-center">
            <div className="p-6 flex flex-col items-center justify-center">
                <h2 className="text-4xl font-semibold text-blue-400">
                    {title}
                </h2>
                {description && (
                    <h6 className="mt-4 text-md font-medium">{description}</h6>
                )}
                <div className="mt-12 w-max">{children}</div>
            </div>
        </div>
    )
}

and it's used here:

const Register: React.FC<RegisterProps> = () => {
    return (
        <FormLayout title="Register" description="Register with your email.">
            {/* form stuff. styles do work in here */}
        </FormLayout>
    )
}

Here are some of the config files:

tailwind config:

module.exports = {
    purge: ['./pages/**/*.{js,ts,jsx,tsx}', './components/**/*.{js,ts,jsx,tsx}'],
    darkMode: 'class',
    theme: {
        extend: {},
    },
    variants: {
        extend: {},
    },
    plugins: [],
}

postcss config:

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

Here is a graphical example of what is happening:

For my build command, I use next build && next export, and Netlify deploys the /out directory.

All the code is here via github

Answer 1

For anyone seeing this in the future, just add the path to any new folder in the purge array into the tailwind config like this:

module.exports = {
    purge: [
        "./src/**/*.{js,ts,jsx,tsx}",
        // Add more here
    ],
    darkMode: 'class',
    theme: {
        extend: {},
    },
    variants: {
        extend: {},
    },
    plugins: [],
}

December 2021 Update:

After TailwindCSS v.3, the config file is slightly different. The above configuration would be:

module.exports = {
  content: [
    "./src/**/*.{js,ts,jsx,tsx}",
    // Add extra paths here
  ],
  theme: {
    extend: {},
  },
  plugins: [],
}

Answer 2

I had the same issue.

I changed these :

purge: [
    "./pages/**/*.{js,ts,jsx,tsx}",
    "./components/**/*.{js,ts,jsx,tsx}",
  ],

to these :

purge: ["./pages/**/*.js", "./components/**/*.js"],

and that's it. problem solved! weird issue

Answer 3

In my case, it was a directory not being listed in the content property of tailwind.config.js file. so any component residing in that directory was not being checked by tailwind.

My new component was in a folder called providers, and it was not listed in content.

so after changing content list to:

 content: [
     // ...
     "./components/**/*.{js,ts,jsx,tsx}",
     "./providers/**/*.{js,ts,jsx,tsx}",  // the key was this line
 ]

The providers directory was also being checked by tailwind. So any directory which consists of a component that uses tailwind utility classes must be included in this list.