What is the Webflow hosting CSS file and why is it large and causing a slow loading time?
TL;DR
- Webflow compiles all styles (including unused ones) into a main CSS file, which can become large and slow page loads.
- To reduce CSS size and improve loading time, audit and remove unused classes, limit combo/custom styles, and avoid importing full frameworks or excessive third-party widgets.
Webflow’s main hosting CSS file is an automatically generated stylesheet that contains all the combined styles for your project. It can grow large and slow down loading if your design includes excessive or unused classes.
1. What Is the Webflow Hosting CSS File?
- Webflow automatically compiles your project’s styles into one or more CSS files when you publish your site.
- These files are named like
site-name.webflow.cssand served through Webflow’s CDN. - They include:
- Styles from the Style panel (global and component-specific)
- Styles from style tags if you use custom CSS
- Code generated by Webflow interactions and symbols
2. Why the CSS File Can Be Large
- If you reuse components without cleaning unused styles, Webflow keeps every style in the compiled CSS.
- Common causes of large CSS files:
- Unused classes from deleted elements or styles
- Combo classes that multiply style variations
- Large amounts of custom code in embedded style tags
- Multiple utility classes applied via Webflow or imported from frameworks like Tailwind or Bootstrap
3. How Large CSS Affects Loading Time
- Web browsers must download and parse the entire CSS file before fully rendering the page (this is render-blocking).
- A large CSS file increases initial page load time, especially on slow connections.
- This affects Core Web Vitals, particularly First Contentful Paint (FCP) and Largest Contentful Paint (LCP).
4. How to Reduce the CSS File Size
- Audit unused classes using Webflow’s built-in clean-up tool or manually in the Style Manager.
- Simplify class usage by minimizing combo classes and reusing base classes where possible.
- Remove unused components like symbols or interactions.
- Use custom code blocks sparingly, and only where necessary.
- Avoid importing full CSS frameworks unless essential.
- Minimize use of third-party embed widgets (they often inject bloated styles or scripts).
5. Tools to Monitor & Test
- Use Chrome DevTools > Coverage tab to check which CSS rules are actually used.
- Use GTmetrix, PageSpeed Insights, or WebPageTest to see how much your CSS contributes to load time.
Summary
Webflow’s hosting CSS file includes all your project’s styles and can become large if many unused or duplicated styles exist. To improve loading time, clean up unused classes, avoid overusing combo classes, and limit custom/third-party code.