CSS custom properties are very powerful way for you to spice up your style sheets. They are a way to separate JavaScript behavior and styling, as shown in the ability to set information in the JavaScript for the CSS to use for its styling.
Even if you’re using a preprocessor for your CSS, there is still a place for CSS custom properties to be directly embedded in your CSS.
In this blog: we introduce custom CSS properties, show why you want to use them, how to define them, and how to change them with and without JavaScript.