message: Fix exporting from nightly where the data-mx-theme is `Light` not `light`
diff: @@ -39,7 +39,8 @@ function mutateCssText(css: string): string {
  const getExportCSS = async (usedClasses: Set<string>): Promise<string> => {
  // only include bundle.css and the data-mx-theme=light styling
  const stylesheets = Array.from(document.styleSheets).filter(s => {
  - return s.href?.endsWith("bundle.css") || (s.ownerNode as HTMLStyleElement).dataset.mxTheme === "light";
  + return s.href?.endsWith("bundle.css") ||
  + (s.ownerNode as HTMLStyleElement).dataset.mxTheme.toLowerCase() === "light";
  });
  let css = "";
  