Day 51 - CSS native mixins and ternary function

?? An Awesome CSS Link a Day – Day 51 ??

W3C drafted Custom Functions @function (CSS Mixins) and if() (ternary function)

Today, we explore one of the most exciting additions coming to CSS: the if() function! Traditionally, CSS has been a declarative language with no built-in conditional logic. But with if(), styles can now react dynamically, without preprocessors or JavaScript. NOTE: Actually available in Chrome Canary with the Experimental Web Platform Features flag enabled.

Introduction

For years, developers have relied on media queries, CSS variables, and JavaScript to implement conditional styles. Now, the if() function allows logic directly inside CSS, enabling scenarios such as:

• Adaptive layouts: "If the viewport is wider than X, adjust the design"
• Theme-based styles: "If dark mode is enabled, change the colors"
• Context-aware spacing: "If a value is positive, apply different margins"

All natively, without extra dependencies.

?? Theory: Custom Functions @function and if() function

The Custom Functions will be a real game-changer, in the example:

@function --negate(--value) {
	result: calc(-1 * var(--value));
}

:root {
  padding: --negate(1px); /* = -1px */
}        

The if() function follows a simple conditional logic, and acts more like a switch:

/*
color: if(
	CONDITION_1: VALUE_1;
	CONDITION_2: VALUE_2;
        ...
	CONDITION_N: VALUE_N;
	else: FALLBACK_VALUE
);
*/

color: if(
	style(--scheme: dark): var(--dark-color);
	style(--scheme: dim): var(--dim-color);
	else: var(--light)
);        

This introduces true conditional styling in CSS, enabling:

• Responsive design without media queries
• More flexible, self-contained components
• New possibilities for color schemes, spacing, and layout logic

When combined with @function, CSS gains even greater logical control over styles.

?? Today’s Link

For a deep dive into if(), @function, and the future of custom CSS functions, check out these articles:

• ?? Bramus: CSS @function and if()
• ?? Bramus: Custom CSS Functions Teaser
• ?? CSS-Tricks: The "Iffy" Future of CSS

?? ??????????????????

• Code snippets showcasing if() in real-world scenarios
• Comparison guide: if() vs. media queries—when to use what
• Practical examples of if() combined with other modern CSS features
• A preview of upcoming CSS custom functions and their potential

? Why This Rocks

• Eliminates JavaScript reliance for many conditional styles
• Reduces media query clutter, making stylesheets more readable
• Paves the way for even more dynamic CSS logic
• Brings CSS closer to functional programming paradigms

??? ???????? ?????? ????????????????????????

• Do you see if() as a replacement for media queries or a complementary tool?
• How would you leverage if() in your current projects?
• What other logical functions would you love to see in CSS?
• Could if() simplify component-based styling in design systems?

Let’s discuss the future of logic-driven CSS! ??