css variables vs sass

CSS Variables vs SASS Variables — Key Differences

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Confused about when to use CSS Variables and when to use SASS Variables? You’re not alone. They sound similar but work very differently. In this MiniCoursey quick guide, you’ll learn how CSS Variables and SASS Variables work, their main differences, and when to use each to write clean, maintainable stylesheets for modern web projects.

How SASS Variables Work

SASS Variables are a feature of the SASS preprocessor. They store values like colors, font sizes, or breakpoints and make them reusable throughout your stylesheet. SASS Variables are replaced at compile time — they don’t exist in the final CSS, so you can’t change them in the browser later.


$primary-color: #007acc;

.button {
  background: $primary-color;
}

How CSS Variables Work

CSS Variables (Custom Properties) are part of native CSS. They’re defined in your CSS and work in the browser at runtime. This means you can change them dynamically with JavaScript or redefine them for specific elements or themes.


:root {
  –primary-color: #007acc;
}

.button {
  background: var(–primary-color);
}

Key Differences

  • Scope: SASS Variables are local to the compiled CSS. CSS Variables inherit and cascade through the DOM.
  • Dynamic: CSS Variables can be updated in the browser. SASS Variables cannot.
  • When Processed: SASS Variables are static and compiled server-side. CSS Variables work in the browser.

💡 Pro Tip: Use SASS Variables for build-time config (like breakpoints) and CSS Variables for themes or dynamic changes.

⚠️ Common Mistake: Don’t try to use SASS Variables in your final browser logic — they’re not available after compile time.

FAQ

Q: Can I use both together?
A: Yes! Many projects combine SASS Variables for structure and CSS Variables for runtime flexibility.

Q: Are CSS Variables widely supported?
A: Yes — modern browsers fully support CSS Variables today.

Related Link

👉 Check out previous: CSS Media Queries — Make Designs Responsive

Where to Learn More

Experiment by building a theme switcher with CSS Variables and a design system using SASS Variables. MDN and SASS official docs are great next stops.

Conclusion

Congrats — you now know when to use CSS Variables vs SASS Variables. Combine both to write flexible, scalable stylesheets for any project.

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