<?php
class cssCompressor {
 private $cssFileName;
 private $selectors = array();
 
 function cssConstruct($cssContent = '', $deleteComments = true){
 $this->cssFileName = $cssContent;
 
 // Delete comments
 if ($deleteComments)
 $this->cssFileName = preg_replace('!/\*[^*]*\*+([^/][^*]*\*+)*/!', '', $this->cssFileName);
 
 $selectors = array();
 // We get all the selectors
 $parties = explode("}", $this->cssFileName);
 
 foreach($parties as $part) {
 if (!empty($part))
 array_push($this->selectors, new SelectorCSS($part."}"));
 }
 }
 
 function get($cleanSpaces = true){
 $output = '';
 foreach($this->selectors as $selector) {
 $output .= $selector->get($cleanSpaces)."\n";
 }
 // Delete line breaks, spaces, ...
 if ($cleanSpaces)
 $output = str_replace(array("\t", "\n", "\r"), '', $output);
 
 return $output;
 }
}
 
/*
 SelectorCSS
*/
class SelectorCSS{
 private $properties = array();
 private $selector;
 
 function cssConstruct($selector = ''){
 $parts = explode("{", $selector);
 if (count($parts) < 2) {
 die("Selector " + selector +" incomplete");
 }
 $this->selector = trim($parts[0]);
 $contents = trim($parts[1]);
 if (strlen($contents) == 0) {
 die("Selector " + selector + "empty");
 }
 
 if (substr($contents,strlen($contents) -1 ,1) != '}'){
 die("Selector "+selector+" is wrong");
 }
 
 $contents = substr($contents, 0, $contents - 2);
 
 $this->properties = explode(';', $contents);
 }
 
 function get(){
 $str = $this->selector.'{';
 natcasesort($this->properties);
 foreach($this->properties as $property) {
 if (!empty($property))
 $str .= $property.";";
 }
 $str .= '}';
 return $str;
 }
 
}
?>

// StyleSheet.css file content
 $fileName = file_get_contents('StyleSheet.css');
 
 // We create an object that we pass the contents of parameter
 $styleSheet = new cssCompressor($fileName);
 /* Parameters:
     1: (String) content of the file
     2: (Bool) Clear comments (default: true)
 */
 // We get the CSS content
 echo $styleSheet->get(false);
 /*    Parameters:
      1: (Bool) Delete lines (default: true)
 */