Ocean dark was just what I was looking for...

[xtiansimon]

...with just one tweak. I reversed the input area color because white was just... too bright.

37 div.input_area {
38   /* Input area with dark background; */
39   background-color: #1e222a; /* added */
40   border-radius: 0px;
41   border: 1px solid #4f5b66;
42 }
43 /* Set light on dark text; */
44 div.CodeMirror-code pre {
45   color: white;  /* added */                                                        
46 }

Cheers!

[nsonnad]

I don't understand what this issue is. Are you saying the input area is white for dark themes? If you are getting that, can you provide a screenshot and browser/OS info?

The default is for the input area to be the same as the background color, and this is the behavior I get for all themes. See this screenshot, for example:

[xtiansimon]

I see the same thing, but when I clicked in a cell to edit, the background of the cell was white (with black text). I was working on markup cells when I altered the CSS. Maybe that makes a difference?
Here's two screen shots...
https://drive.google.com/file/d/0B7q1i4T96t6eUG5mNjl1NXRfX0E/edit?usp=sharing
https://drive.google.com/file/d/0B7q1i4T96t6eZU9jN2tpTmFELVk/edit?usp=sharing