Pressbooks\Modules\Export\Prince\Pdf::kneadCss PHP Method

    protected function kneadCss()
    {
        $sass = Container::get('Sass');
        $scss_dir = pathinfo($this->exportStylePath, PATHINFO_DIRNAME);
        $scss = $sass->applyOverrides(file_get_contents($this->exportStylePath), $this->cssOverrides);
        if ($sass->isCurrentThemeCompatible(1)) {
            $css = $sass->compile($scss, [$sass->pathToUserGeneratedSass(), $sass->pathToPartials(), $sass->pathToFonts(), get_stylesheet_directory()]);
        } elseif ($sass->isCurrentThemeCompatible(2)) {
            $css = $sass->compile($scss, $sass->defaultIncludePaths('prince'));
        } else {
            $css = static::injectHouseStyles($scss);
        }
        // Search for url("*"), url('*'), and url(*)
        $url_regex = '/url\\(([\\s])?([\\"|\'])?(.*?)([\\"|\'])?([\\s])?\\)/i';
        $css = preg_replace_callback($url_regex, function ($matches) use($scss_dir) {
            $url = $matches[3];
            if (preg_match('#^themes-book/pressbooks-book/fonts/[a-zA-Z0-9_-]+(\\.woff|\\.otf|\\.ttf)$#i', $url)) {
                $my_asset = realpath(PB_PLUGIN_DIR . $url);
                if ($my_asset) {
                    return 'url(' . PB_PLUGIN_DIR . $url . ')';
                }
            } elseif (preg_match('#^uploads/assets/fonts/[a-zA-Z0-9_-]+(\\.woff|\\.otf|\\.ttf)$#i', $url)) {
                $my_asset = realpath(WP_CONTENT_DIR . '/' . $url);
                if ($my_asset) {
                    return 'url(' . WP_CONTENT_DIR . '/' . $url . ')';
                }
            } elseif (!preg_match('#^https?://#i', $url)) {
                $my_asset = realpath("{$scss_dir}/{$url}");
                if ($my_asset) {
                    return "url({$scss_dir}/{$url})";
                }
            }
            return $matches[0];
            // No change
        }, $css);
        if (WP_DEBUG) {
            Container::get('Sass')->debug($css, $scss, 'prince');
        }
        return $css;
    }