jiayihu

function copyStyles(sourceDoc, targetDoc) {
  Array.from(sourceDoc.styleSheets).forEach(styleSheet => {
    if (styleSheet.cssRules) { // for <style> elements
      const newStyleEl = sourceDoc.createElement('style');

      Array.from(styleSheet.cssRules).forEach(cssRule => {
        // write the text of each rule into the body of the style element
        newStyleEl.appendChild(sourceDoc.createTextNode(cssRule.cssText));
      });