1. SASS / SCSS

SASS (Syntactically Awesome Style Sheets) is a powerful CSS preprocessor that adds variables, nesting, mixins, functions, and more. SCSS is its modern syntax, fully compatible with CSS.

CSS Example

$primary-color: #3498db;

.button {
  background-color: $primary-color;
  color: white;
  padding: 10px 20px;
  &:hover {
    background-color: darken($primary-color, 10%);
  }
}

2. LESS

LESS is another CSS preprocessor similar to SASS. It supports variables, mixins, nesting, and operations, and is widely used in projects like Bootstrap.

CSS Example

@primary-color: #e74c3c;

.button {
  background-color: @primary-color;
  color: white;
  padding: 10px 20px;
  &:hover {
    background-color: darken(@primary-color, 10%);
  }
}

3. PostCSS

PostCSS is a tool that transforms CSS with JavaScript plugins. It can autoprefix, lint, and add modern CSS features, making it a core part of modern front-end workflows.

CSS Example

/* Example using PostCSS plugin autoprefixer */
.button {
  display: flex;
  transition: transform 0.3s;
}

.button:hover {
  transform: scale(1.1);
}

4. Autoprefixer

Autoprefixer automatically adds vendor prefixes to CSS properties for better browser support. It is commonly used with PostCSS to simplify cross-browser compatibility.

CSS Example

.box {
  display: flex;
  transition: transform 0.3s;
}
.box:hover {
  transform: scale(1.1);
}
/* Autoprefixer adds vendor prefixes like -webkit- or -ms- automatically */