Replying to: Michiel Bijl
Unless we get some figures on how people achieve or use this setting, I think it is best to declare both. It’s not like background: #fff; is a whole lot to type.
Safari 8 on OS X 10.10 doesn’t even offer a user friendly way to change either of these settings. The only option is to define a user stylesheet. So you’d have to be familiar with CSS to change anything.
Firefox 33 does offer these settings. They even offer you to disable websites from overwriting your preference.
Even with the build-in search, I was unable to find these settings in Chrome (...)