public function combineCssFiles($inputFiles, $outputFile)
{
$content = '';
$outputFilePath = dirname($this->findRealPath($outputFile));
foreach ($inputFiles as $file) {
$content .= "/*** BEGIN FILE: {$file} ***/\n" . $this->adjustCssUrl(file_get_contents($file), dirname($this->findRealPath($file)), $outputFilePath) . "/*** END FILE: {$file} ***/\n";
}
if (!file_put_contents($outputFile, $content)) {
throw new Exception("Unable to write output CSS file '{$outputFile}'.");
}
}