CSS Variables, also known as Custom Properties, enable developers to store values that can be reused throughout the stylesheet. They allow for more flexible and maintainable code by centralizing values such as colors, fonts, and spacing.

Syntax and Declaration:

CSS Variables are declared within a selector using the --variable-name syntax and are accessed using the var(--variable-name) function. They are typically defined in the :root selector to ensure global accessibility.

Benefits of Using CSS Variables:

By using CSS Variables, you can significantly reduce redundancy in your stylesheets. They allow for easy updates, theme switching, and responsive design adjustments without altering multiple code instances.

Browser Support:

CSS Variables are supported by all modern browsers. However, it is essential to check compatibility for older versions if supporting legacy systems.

Practical Example:

Let's explore a simple example where CSS Variables are used to define a color scheme for a website.


:root {
  --primary-color: #3498db;
  --secondary-color: #2ecc71;
  --font-color: #333;
}

body {
  color: var(--font-color);
  background-color: var(--primary-color);
}

button {
  background-color: var(--secondary-color);
  color: #fff;
}

Dynamic Theme Change:

CSS Variables make it easy to implement dynamic theme changes. By altering the variable values, you can switch themes without modifying each style rule individually.

Using JavaScript with CSS Variables:

JavaScript can dynamically update CSS Variable values, allowing for interactive and responsive design changes based on user actions or other events.

Fallback Values:

When using CSS Variables, you can specify fallback values to ensure proper rendering if a variable is not defined. This is done by adding a second parameter to the var() function.

Scope and Inheritance:

CSS Variables are scoped to the element they are declared on and inherit down the DOM tree. This allows for context-specific variable definitions and overrides.

Limitations:

While CSS Variables offer significant flexibility, they cannot be used in certain CSS properties like selectors or media queries. Understanding these limitations is crucial for effective use.

Console Output:

No console output for CSS.