CSS preprocessors are scripting languages that extend the capabilities of CSS, making it easier for developers to write and maintain their stylesheets. Popular CSS preprocessors include SASS and LESS. Both of these preprocessors provide a range of features that can make writing CSS more efficient and maintainable.

One of the main benefits of using a CSS preprocessor is the ability to use variables. This allows developers to store values, such as colors and font sizes, in a single location and then reuse them throughout their stylesheets. This makes it much easier to make global changes to a website’s design, and also helps to keep the code more organized.

$primary-color: #333;
$secondary-color: #777;

body {
  background-color: $primary-color;
  color: $secondary-color;
}

CSS preprocessors also provide the ability to nest selectors, which can make the code more readable and maintainable. This allows developers to organize their styles into logical groups, which can make it easier to find and modify specific styles later on.

nav {
  ul {
    list-style: none;
    li {
      display: inline-block;
    }
  }
}

Another benefit of using a CSS preprocessor is the ability to use functions and mixins. A mixin is a reusable block of CSS that can be included in multiple selectors. This allows developers to write complex styles, such as CSS3 transforms and transitions, and then reuse them throughout their stylesheets.

@mixin transform($property) {
  -webkit-transform: $property;
  -ms-transform: $property;
  transform: $property;
}

.box {
  @include transform(rotate(30deg));
}

In conclusion, CSS preprocessors like SASS and LESS provide a range of benefits that can make writing and maintaining CSS easier. They allow developers to use variables, nest selectors, use functions and mixins, which improves code readability and maintainability. These preprocessors also allow developers to write complex styles and reuse them throughout their stylesheets, making the development process much more efficient.