Start off by using Se7ensins defualt light theme, then apply this!

Only really looks good with the default colour setting ATM.
Full support for custom colours are not yet done with the secondary colour (green),
and content text color (#CCC).

See full thread here: http://www.se7ensins.com/forums/threads/stylish-ultimate-dark-theme-coming-soon.1539110

===[ Instructions! ]===
I have listed the colors you can pick by number, for example #1 is the "Light gray" with a hex of #252525. I will refer to the numbers while instructing.

– Color #1 should be lighter than #2, else it may end up looking weird.

– If color #1 and #2 is light, you may want to pick a darker #3.

– You should generally not mess with #3 unless necessary. If you do, you may need to change #6.

– #4 is the theme color. This color will be everywhere. #5 is the same color, only slightly darker for hover effect reasons.

– If the #4 color is a light or dark color, the text on top of it may be hard to read. In that case, you should adjust #6 to go well on that background.

– Color #7 is the color of your marking. When you mark text, that's the background color.
– Color #8 is the color of the text when marking the text, so pick a color that is readable over #7.