PDF export contains white background when base URL is correct

Description

When the user tries to export a space to pdf with some pdf stylesheet, the pdf is generated with a white background. However, when the user modifies the base URL to an incorrect base URL, the white background is not appearing.

Steps to reproduce

1. Install confluence
2. Set the base url as http://localhost:8090
3. Access confluence with http://localhost:8090
4. Create a new space
5. Apply the following pdf stylesheet to space

   @page {  
       background-color: red;
   }
   

6. Export the space to pdf

Expected Result
The background of the pdf is red
KT2-240717-1717-8 working.pdf

Actual Result
There is a white background in pdf
KT2-240717-1716-4 not working.pdf