core-bundle/src/Resources/contao/library/Contao/Combiner.php
protected function hasMediaTag($strFile)
	{
		$return = false;
		$fh = fopen($this->strRootDir . '/' . $strFile, 'rb');

		while (($line = fgets($fh)) !== false)
		{
			if (strpos($line, '@media') !== false)
			{
				$return = true;
				break;
			}
		}

		fclose($fh);

		return $return;
	}
protected function hasMediaTag($strFile)
	{
		$return = false;
		$fh = fopen($this->strRootDir . '/' . $strFile, 'rb');

		while (($line = fgets($fh)) !== false)
		{
			if (strpos($line, '@media') !== false)
			{
				$return = true;
				break;
			}
		}

		fclose($fh);

		return $return;
	}
Check if the file has a @media tag

@param string $strFile

@return boolean True if the file has a @media tag