CSS preprocessor (nested constructs, constants, arithmetic expressions)

Question

PHP

Tell me a preprocessor (if you can call it that) for CSS that supports nested constructs, constants, arithmetic expressions, while using the syntax of the source file as close as possible to CSS (and not, for example, XML). It is desirable either in PHP, or a separate console application for Windows. Interested in also a solution in the form of a module for Apache.

For example:

.header {
margin: marginVar - 10;
a {
…
}
}

Answer 1

leafo.net/lessphp/docs/

Answer 2

SASS ?

Answer 3

or for example github.com/cloudhead/less.js
which has a more native syntax compared to SASS/SCSS

Answer 4

The SCSS syntax is basically the same as CSS!
It has everything you listed and more, such as conditional statements or loop statements.
A good thing is the "Compass" framework. It's based on SASS (SCSS, to be exact) and includes a lot of goodies, but to install it, you'll need the Ruby gem and have to work from the command line.
If you don't like dancing with a tambourine - google ScoutApp. The only free application for Windows so far, but very slow.