CSS preprocessor variables are powerful tools that enhance the functionality of traditional CSS. They allow developers to define reusable values throughout their stylesheets, making code more maintainable and flexible.
CSS preprocessor variables are placeholders for values that can be reused across a stylesheet. They're defined using a specific syntax and are processed before the CSS is compiled, resulting in standard CSS output.
The syntax for defining and using variables varies slightly between different CSS preprocessors. Here's an example using Sass:
$primary-color: #3498db;
.button {
background-color: $primary-color;
color: white;
}
In this example, $primary-color is a variable that stores a color value. It can be reused throughout the stylesheet, making it easy to update the color scheme globally.
CSS preprocessor variables can have different scopes, allowing for local and global variables. They can also be nested within selectors:
$global-font: Arial, sans-serif;
.container {
$local-padding: 20px;
font-family: $global-font;
padding: $local-padding;
.inner {
padding: $local-padding / 2;
}
}
Many preprocessors allow mathematical operations with variables:
$base-size: 16px;
$heading-size: $base-size * 1.5;
h1 {
font-size: $heading-size;
}
While preprocessor variables are not native to CSS, they compile into standard CSS. For native CSS variables, refer to CSS Custom Properties.
CSS preprocessor variables significantly enhance the development process by introducing programming concepts to stylesheets. They work seamlessly with other preprocessor features like mixins and nesting, creating a more robust styling system.