An edit of http://freestyler.ws/style/42612/emacs-wiki-black. This makes some sections darker and adds a few other subtleties.

The Emacs Wiki https://www.emacswiki.org/emacs?action=browse;id=CSS;css=/light.css;theme=dark is also a sufficient alternative to this style since it is maintained by Emacs Wiki itself and is rather nice. Emacs Wiki will set this as your default upon selecting it as it will set a cookie for the style. You can view other styles to choose from https://www.emacswiki.org/emacs/CSS.

Caveat: this style works better in WebKit-based browsers, such as Google Chrome or Safari, as it uses a WebKit-only property to darken some elements.