Website colors are wrong
From MozillaZine Knowledge Base
If webpages' background and text colors are displaying wrong, try checking the following settings:
- (Firefox) View -> Page Style should not be set to "No Style"
- "Tools -> Options -> Content -> Colors" check "Allow pages to use their own colors, instead of my selections above"
- (Windows users) Start Menu -> Control Panel -> Accessibility -> Display -> uncheck "Use High Contrast", restart the application
- (Windows users) Right-click the Firefox shortcut -> Properties -> Compatibility -> uncheck "Run in 256 colors", restart the application
If none of those settings work, try it on another system. If the other system also has the same issues, it's likely a problem with the site.