How can I make TeXWorks display its PDF preview with a black background?

How can I make TeXWorks display its PDF preview so that the background is black, text is (by default) white, and shades of grey are also displayed appropriately?

The answers to this question help somewhat, but the sticking-point is the background colour of the PDF preview window. (In order to reduce strain on my eyes, I have tried applying a "white" theme .css to Texworks, then using another utility to reverse-video the entire screen, but then that makes switching between apps painful.)

I know about the file

< MiKTeX installation directory>TeXworks.6configurationsyntax-patterns.txt.

I have used Windows 8.1 to map the taskbar’s TexWorks icon to

< MiKTeX installation directory>miktexbinx64miktex-texworks.exe -stylesheet < my CSS file>

The file syntax-patterns.txt seems to be exclusively concerned with the formatting of the TeX-editing window, not the PDF preview window.

Windows 8.1, MiKTeX 2.9, TeXWorks 0.6