code: function fixRelativeCssUrls(cssText, baseUrl) {
      const cssUrls = cssText
          // Remove comments
          .replace(regex.cssComments, '')
          // Match url(...) values
          .match(regex.cssUrls) || [];
  
      cssUrls.forEach(cssUrl => {
          const oldUrl = cssUrl.replace(regex.cssUrls, '$1');
          const newUrl = getFullUrl(oldUrl, baseUrl);
  
          cssText = cssText.replace(cssUrl, cssUrl.replace(oldUrl, newUrl));
      });
  
      return cssText;
  }
docs: Convert relative CSS url(...) values to absolute based on baseUrl
  
  @param {string} cssText
  @param {string} baseUrl
  @returns {string}