message: Initialize css string
diff: @@ -25,7 +25,7 @@ const getExportCSS = async (): Promise<string> => {
  stylesheets.push(e.href);
  }
  });
  - let CSS: string;
  + let CSS = "";
  for (const stylesheet of stylesheets) {
  const res = await fetch(stylesheet);
  const innerText = await res.text();
  