loading delay of module css with nextjs #76752

AnkityadavIITR · 2025-03-03T10:35:52Z

AnkityadavIITR
Mar 3, 2025

Summary

I was recently working on Nextjs project with ant design components along with module CSS and can't unnoticed the significant time delay in loading the CSS on the production...never faced this issue with tailwind. is there any middleware or config setting which can be used to avoid this particular behaviour

Additional information

No response

Example

https://www.tektoor.com/ this website using module css

Aman3899 · 2025-03-07T06:18:38Z

Aman3899
Mar 7, 2025

Possible Causes & Fixes

Optimize CSS Handling in Next.js
- Ensure that you're using the recommended Next.js CSS setup. If you're importing CSS modules inside components, Next.js should automatically optimize them.
- If you're importing a large global CSS file, consider splitting styles into smaller, more modular styles.
Enable Next.js SWC Minification & Optimize Ant Design Imports
- Ensure that SWC minification is enabled in next.config.js:
```
module.exports = {
  swcMinify: true,
};
```
- Instead of importing all Ant Design styles globally, import only the required components to reduce unnecessary CSS loading:
```
import "antd/lib/button/style/css"; // Instead of importing entire antd CSS
```

Prefetch & Preload CSS in _document.js

You can explicitly preload critical styles in your custom _document.js file:

import Document, { Html, Head, Main, NextScript } from 'next/document';

class MyDocument extends Document {
  render() {
    return (
      <Html lang="en">
        <Head>
          <link rel="preload" href="/_next/static/css/styles.css" as="style" />
        </Head>
        <body>
          <Main />
          <NextScript />
        </body>
      </Html>
    );
  }
}

export default MyDocument;

Reduce Render Blocking CSS
- Next.js automatically inlines critical CSS, but you can manually optimize render-blocking styles by using the next/script component to load non-critical styles asynchronously.
Check Your Hosting & Caching Settings
- If you're hosting on Vercel, Netlify, or another cloud provider, ensure that caching headers for static assets are properly configured.
- Use Next.js static exports (next export) to generate a static build and serve pre-built pages for better performance.

Why Tailwind Feels Faster?

Tailwind generates optimized atomic classes, reducing unused styles, whereas CSS modules generate unique class names that require additional processing. If performance is a major concern, you could consider moving critical styles to Tailwind and keeping CSS modules for scoped styles.

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loading delay of module css with nextjs #76752

AnkityadavIITR Mar 3, 2025

Summary

Additional information

Example

Replies: 1 comment

Aman3899 Mar 7, 2025

Possible Causes & Fixes

Why Tailwind Feels Faster?

AnkityadavIITR
Mar 3, 2025

Aman3899
Mar 7, 2025