if()
Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.
The if() CSS function allows different values to be set for a property depending on the result of a conditional test. The test can be based on a style query, a media query, or a feature query.
Browser support
| Feature | Desktop | Mobile | ||||
|---|---|---|---|---|---|---|
| Chrome | Edge | Firefox | Safari | Chrome Android | Safari iOS | |
if Experimental | 137 | 137 | | | 137 | |
1+Supported (version) Not supported ※Has note Sub-feature descriptions sourced from MDN Web Docs (CC BY-SA 2.5)
Syntax
CSS
.box {
color: if(
style(--theme: dark): white;
else: black
);
}Live demo
Use cases
-
Use if()
Use if() when the default CSS behavior is not expressive enough for the component or layout you are building.
-
Handle edge cases
Apply if() to solve a specific styling constraint without introducing broader layout or behavior changes.
Cautions
- Test if() in the browsers you support, especially if it changes layout, text handling, or interaction behavior.
- Plan a fallback or acceptable degradation path when support is still limited.
Accessibility
- Confirm that using if() does not make content harder to perceive, understand, or operate in assistive contexts.