What are CSS variables?The CSS variables are more accurately known as CSS custom properties. You can define a value under a variable key and use it along your stylesheets wherever is in its scope. They can be very useful to avoid CSS repetition, with a better performance in run time for things like theme switching and very useful for extending or ‘polyfilling’ future CSS features.
What is React?React (sometimes called also ReactJs) is a library to create reusable components and build with that your web applications. Its development was leaded by Facebook development teams. Nowadays is pretty widely used around the world and there is a high demand of professionals with knowdledge and experience with the technology.