I noticed that since the beginning Google is not allowing to change background colour of it’s pages. It is pity, as if you take for example DuckDuckGo you are able to modify the background color easialy: DuckDuckGo Settings page. Moreover, you can easily specify to use always HTTPS, which is not yet the case for Google.
I prefer usually gray colors, as the white color is too bright for my eyes. Background with C4C4C4 seems to be ideal for me, and since I am fun of customization, I guess, I will have to use DuckDuckGo for a while 🙂