public function getCssContent(string $fileName, bool $minify): string
    {
        $content = file_get_contents($fileName);

        if ($content === false) {
            throw new RuntimeException(sprintf('File could be read: %s', $fileName));
        }

        if ($minify === true) {
            $compressor = new CssMinifier();
            $content = $compressor->run($content);
        }

        return $content;
    }