XSSFWorkbook bold font not working

问题:

Code is as follows, is there something wrong with it?

Workbook wb = new XSSFWorkbook();
Sheet sheet = wb.createSheet();
Row row=sheet.createRow(0);

Font font= wb.createFont();
font.setBold(true);

CellStyle style = wb.createCellStyle();
style.setFont(font);
Cell cell = row.createCell(0);
cell.setCellValue("hello你好");
cell.setCellStyle(style);
try {
    // Write the output to a file
    FileOutputStream fileOut = new FileOutputStream("test.xlsx");
    wb.write(fileOut);
    fileOut.close();
}
catch (Exception e) {
    System.out.print(e.getMessage());
}

I'm using Mac Numbers testing the generated excel file.

Note: The code abouve works when switch XSSFWorkbook to HSSFWorkbook.