忽略背景颜色 - DOMPDF

I am generating PDFs using DOMPDF. Everything works fine. However, when I open the pdf file I can see the default grey background color. I had some other tables to print but it had the same issue, I thought may be something is wrong with my CSS. I tried to change the background color of all divs and tables but nothing worked. Therefore, I decided to print only dummy data with no css to see if there is any other issue. When i tried to print the only one word then below is the result i can see in PDF.

So, I am wondering how can i change it in to white color.

Following is my simple 5 lines code to generate this.

    $dompdf = new DOMPDF();
    $dompdf->load_html($listing);
    $dompdf->set_paper('a4', 'landscape');
    $dompdf->render();
   file_put_contents('file.pdf', $dompdf->output());