Section 508 requirements

I am designing a website that has to take into account Section 508 requirements. They usually concern providing a description for images using the alt element and providing a key-entered alternative to access various form fields. All can be found here:

https://www.hhs.gov/web/section-508/making-files-accessible/checklist/html/index.html

Several of the questions deal with CSS disabled. My question is since text should be visible even with CSS disabled, does that mean that I should plan on black text on a white background only? I don't know if white text on a black background will even be visible with CSS disabled.