We posted not long ago about the difference between native CSS variables (custom properties) and preprocessor variables. There are a few esoteric things
This tutorial teaches you CSS Variables through eight interactive screencasts. It's value-packed from beginning to end, and is probably the fastest way to get an in-depth understanding of CSS Variables.
CSS Custom Properties In The Cascade — Smashing Magazine
In this article, Miriam takes a deeper dive into the ‘CSS Custom Properties for Cascading Variables’ specification to ask, “Why are they called custom properties, how do they work in the cascade, and what else can we do with them?”
Building Robust Layouts With Container Units — Smashing Magazine
When inspecting most other grids in DevTools, you’ll notice that column widths are dependent on their parent element. This article will help you understand how to overcome these limitations using CSS variables and how you can start building with container units.
Learn About CSS Custom Properties Through Clever Uses of Them - DEV Community 👩💻👨💻
CSS custom properties have a ton of use cases. They have all the power of traditional variables, only they follow the cascade like we expect in CSS. Plus you can get clever with their values and combine them with other CSS technology to do very interesting things.
CSS Custom Properties ("CSS-Variable") für die Website-Gestaltung verwenden
CSS Custom Properties - Gestalten Sie Ihre Website flexibler und schneller mit CSS-Variablen. Eine kurze Einführung in CSS Custom Properties mit Beispielen und Theming.
Variablen (Custom Properties) ändern CSS-Werte wie Farben und Größen für mehrere Elemente im gesamten CSS. Variablen vereinfachen Änderungen im Design.
CSS Custom Properties in Microsoft Edge - Microsoft Edge Blog
Beginning with EdgeHTML 15 in the Windows 10 Creators Update, Microsoft Edge introduces support for CSS Custom Properties, a new primitive value type to fully cascade variables across CSS properties. You can preview CSS Custom Properties in Windows Insider Preview builds beginning with EdgeHTML 15.15061. Check out our Custom Properties Pooch demo to see them