Reset All Font Sizes in Google Docs Using Google Apps Script

function resetFontSizeAndStyle() {
  const doc = DocumentApp.getActiveDocument();
  const body = doc.getBody();
  const paragraphs = body.getParagraphs();

  paragraphs.forEach(paragraph => {
    const text = paragraph.editAsText();
    if (text) {
      // Reset font size and font family to default
      text.setFontSize(null);
      text.setFontFamily(null);
    }
  });
}