Click and drag the following link to your bookmarks bar. This will create a "bookmarklet", a small script that runs whenever you click it.---> [K] NightMode v7 <--- Drag this link to your bookmarks bar!
To activate night-mode, simply click your new bookmark and the page will turn dark. Reloading the page will reset it. This only works on Kongregate game pages.
Current version: v7 (Jan 19, 2014). Compatibility with Chat Line Highlighting script.