CSS if() Is Here: Smarter Styling with Conditional Logic

CSS just got a major upgrade. With the new if() statement, you can apply styles conditionally—without JavaScript or preprocessor hacks. Here’s what you need to know.

For years, developers have relied on media queries, custom class toggles, or even JavaScript to conditionally apply CSS rules. Now, CSS is entering a new era with native conditional logic thanks to the introduction of the if() function.

🔍 What Is the if() Function in CSS?

The new if() syntax lets you apply CSS property values based on certain conditions—like screen size, feature support, or custom variable states. This is a powerful step toward dynamic, responsive design without bloated stylesheets.

color: if(
  media(width < 500px): blue;
  supports(color: lch(50% 50 200)): lch(50% 50 200);
  else: black;
);

Think of it like a cascading conditional structure—if the media condition is true, use blue; if not, but the browser supports lch() color, use that; otherwise, fall back to black.

✨ Practical Use Cases

• Responsive Design:
  font-size: if(media(width > 768px): 1.5rem; else: 1rem;)
• Theming with CSS Variables:
  background-color: if(style(--dark-mode: true): #111; else: #fff;)
• Graceful Feature Fallbacks:
  color: if(supports(color: lch(60% 20 180)): lch(60% 20 180); else: #333;)

🧪 Browser Support

As of now, the if() function is considered experimental and is only supported in the latest version of Chrome (version 137 and above) with flags enabled. Other browsers are expected to adopt it in future releases, but developers should continue using fallbacks for production code.

/* Fallback first */
padding: 1rem;

/* Conditional override (if supported) */
padding: if(media(width > 600px): 2rem; else: 0.5rem;);

This ensures your design remains functional and accessible in environments that don’t yet support the new feature.

🛠 Advantages Over Traditional Methods

• Eliminates extra classes or scripting: Dynamic styling can now be purely CSS-based.
• Simplifies conditional logic: Especially for media queries and feature support.
• Reduces stylesheet complexity: No need to write multiple selectors or deeply nested media queries.

⚠️ Things to Keep in Mind

• Still experimental: Avoid production use unless you’re targeting very specific browser versions.
• Always include fallbacks: Place traditional CSS rules before if() statements to maintain graceful degradation.
• Monitor browser compatibility: Watch updates from Chrome, Firefox, and Safari as this feature rolls out.

🚀 Getting Started

1. Update Chrome to version 137+ and enable the experimental Web Platform features flag.
2. Test if() inside dev tools or small sandbox projects.
3. Use feature detection with @supports or if(supports(...)) to experiment with cutting-edge CSS.

Conclusion

The introduction of the if() function marks a huge leap forward for CSS. It adds a layer of intelligence that previously required JavaScript or preprocessors. While the feature is still in its infancy, its potential for writing cleaner, smarter, and more adaptive stylesheets is exciting.

Keep an eye on browser adoption, start testing today, and be ready to level up your CSS game when support becomes mainstream.

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