Using the CSS if() Function for Conditional Styling

CSS conditional styling has traditionally relied on media queries, container queries, and custom property workarounds. The new CSS if() function changes this by bringing inline conditional logic directly to property values. As of August 2025, this feature is available in Chrome 137+, Edge 137+, Chrome for Android, and Android Browser, offering developers a cleaner approach to dynamic styling.

This article explores the if() function’s syntax, its three query types, and practical applications that demonstrate why it’s becoming an essential tool for modern CSS development.

Understanding the CSS if() Function Syntax

The CSS if() function follows a specific pattern that sets it apart from other CSS functions:

property: if(condition: value; else: fallback);

Notice the semicolon separating condition-value pairs—not commas like other CSS functions. You can also chain multiple conditions:

property: if(
  condition-1: value-1;
  condition-2: value-2;
  condition-3: value-3;
  else: fallback
);

The function requires no space between if and the opening parenthesis. This strict syntax helps the CSS parser distinguish between multiple conditions within a single function call.

Three Types of Conditional Queries

style() Queries

The style() query checks custom property values on the current element:

.button {
  background: if(
    style(--variant: primary): #0066cc;
    else: transparent
  );
}

Unlike container style queries, style() within if() applies directly to the styled element—no parent container needed.

media() Queries

Media queries work inline, eliminating the need for separate rule blocks:

.nav-item {
  padding: if(
    media(min-width: 768px): 16px 24px;
    else: 8px 12px
  );
}

supports() Queries

Test for CSS feature support directly within property values:

.container {
  display: if(
    supports(display: grid): grid;
    else: flex
  );
}

Real-World Example: Adaptive Button Sizing

Let’s create a button that adapts its size based on the user’s input method—a common accessibility requirement:

button {
  /* Touch-friendly sizing for coarse pointers */
  width: if(media(any-pointer: coarse): 44px; else: 30px);
  height: if(media(any-pointer: coarse): 44px; else: 30px);
  
  /* Adjust padding accordingly */
  padding: if(
    media(any-pointer: coarse): 12px 16px;
    else: 8px 12px
  );
  
  /* Maintain consistent styling */
  border-radius: 6px;
  transition: all 0.2s ease;
}

This approach keeps all responsive logic inline with each property, making the component’s behavior immediately clear without jumping between rule blocks.

Theme Switching with Conditional Styling

Design systems often require multiple themes. The if() function excels at this pattern:

:root {
  --theme: ocean; /* or forest or sunset */
}

.card {
  background: if(
    style(--theme: ocean): #e3f2fd;
    style(--theme: forest): #e8f5e9;
    style(--theme: sunset): #fff3e0;
    else: #ffffff
  );
  
  color: if(
    style(--theme: ocean): #0d47a1;
    style(--theme: forest): #1b5e20;
    style(--theme: sunset): #e65100;
    else: #333333
  );
  
  border: 2px solid if(
    style(--theme: ocean): #1976d2;
    style(--theme: forest): #388e3c;
    style(--theme: sunset): #f57c00;
    else: #cccccc
  );
}

To switch themes, simply update the custom property:

.ocean-theme { --theme: ocean; }
.forest-theme { --theme: forest; }
.sunset-theme { --theme: sunset; }

Comparing if() to Traditional Approaches

The if() function offers advantages over existing conditional CSS patterns:

vs. Media Queries:

• Keeps logic inline rather than scattered across rule blocks
• Reduces code duplication
• Makes component behavior more transparent

vs. Custom Property Toggles:

• More readable and explicit
• No need for complex calc() workarounds
• Self-documenting code

vs. Container Style Queries:

• Applies directly to elements without parent dependencies
• Simpler syntax for single-property conditions
• Better for component-level styling

Browser Support and Implementation

Currently, the CSS if() function is supported in:

• Chrome 137+
• Edge 137+
• Chrome for Android
• Android Browser

For unsupported browsers, continue using traditional approaches as fallbacks. The limited support means production use requires careful consideration of your user base.

For detailed specifications and updates, refer to the MDN Web Docs for the CSS if() Function.

Conclusion

The CSS if() function represents a significant step forward in conditional styling. By bringing logic inline with property declarations, it creates more maintainable and understandable stylesheets. While browser support remains limited, the function’s potential for cleaner theming, responsive design, and state-based styling makes it worth exploring for future projects.

As browser adoption grows, expect the if() function to become a standard tool for handling conditional CSS, replacing many current workarounds with cleaner, more intuitive syntax.

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