createCssFile(href) {
    var newUrl;

    if (path_default.a.isAbsolute(href)) {
      return new Promise(function (resolve) {
        resolve();
      });
    }

    var absolute = this.settings.resolver(href); // Get the text of the css file from the archive

    var textResponse;

    if (this.settings.archive) {
      textResponse = this.settings.archive.getText(absolute);
    } else {
      textResponse = this.settings.request(absolute, "text");
    } // Get asset links relative to css file


    var relUrls = this.urls.map(assetHref => {
      var resolved = this.settings.resolver(assetHref);
      var relative = new utils_path["a" /* default */](absolute).relative(resolved);
      return relative;
    });

    if (!textResponse) {
      // file not found, don't replace
      return new Promise(function (resolve) {
        resolve();
      });
    }

    return textResponse.then(text => {
      // Replacements in the css text
      text = Object(replacements["e" /* substitute */])(text, relUrls, this.replacementUrls); // Get the new url

      if (this.settings.replacements === "base64") {
        newUrl = Object(core["createBase64Url"])(text, "text/css");
      } else {
        newUrl = Object(core["createBlobUrl"])(text, "text/css");
      }

      return newUrl;
    }, err => {
      // handle response errors
      return new Promise(function (resolve) {
        resolve();
      });
    });
  }
Create a new CSS file with the replaced URLs
@private
@param  {string} href the original css file
@return {Promise}  returns a BlobUrl to the new CSS file or a data url