How to use CSS variables like a pro

CSS variables, also known as custom properties, allow developers to reuse values throughout a stylesheet, helping to write clean and efficient code. This tutorial provides a detailed guide on using CSS variables with practical examples, including dynamic changes with JavaScript, responsive design adjustments, and theme toggling. Learn how to define CSS variables globally or locally, apply fallback values, and harness cascading rules and specificities for styling flexibility.

#webdev

#javascript

#css

#frontend

Mar 21, 2025•25m read time•From blog.logrocket.com

Table of contents

See how LogRocket's AI-powered error tracking works What are CSS variables?What we’ll build in this tutorial How to declare and use CSS variables Over 200k developers use LogRocket to create better digital experiences Project 1: Building button variations Project 2: Setting CSS variables dynamically with JavaScript Project 3: Handling responsive design features Project 4: Generating JavaScript-free dynamic elements CSS variables vs. SASS variables Advanced techniques: Using CSS variables in animations Browser support for the CSS variables feature Common mistakes & troubleshooting CSS variables Conclusion Frequently asked questions Is your frontend hogging your users' CPU?