Using the Google Chrome plugin Stylish, users can add custom CSS to be applied to any domain. I’ve created a dark CSS theme for Facebook, called FaceBook IDE

Within Stylish (found in the Chome menu bar):

Write a new style

Paste the theme into the box

Add the domain “facebook.com” into the “applies to” field

The theme should automatically apply to your Facebook news feed. This theme is still in development, and has areas on other Facebook pages, which are not yet styled.