[Nexus 10 Themes and Apps] 3DSammy:
I'm a big fan of the Blacked out themed apps, I wanted to do the same for Web pages. Here is a solution for any browser: Web Browser With Black Background (Invert Colors / Night Mode) Through Proxy Filter. Full credit goes to claimui.

Implementation:

HTML pages are filtered by a local non-caching Proxy server (localhost:8118) which dynamically modifies HTML pages to insert a CSS style sheet which replaces background/text/link colors. Web browsers display the modified HTML with black backgrounds, light gray text and green links.

Pros:

1) This is a Web browser agnostic solution (AOSP, Chrome, Ocean, Next ... etc)

2) Unlike using an "Inverse rendering" option, graphics display as intended

3) Extends blacked out theming to apps that display HTML (e.g. Flipboard)

4) With a text editor you can modify the theme for HTML pages to any combination of colors you wish

5) The speed of the filtering is non-obtrusive

6) No negative impact on any other network traffic (YouTube, Email ... etc)

Cons:

1) Cannot be use along side another local proxy server such as an ad-blocker (e.g. Adblock Plus). See: *

2) The proxy is specific to a WiFi connection. With JB 4.2.x/4.3 there is no method to set Ethernet adapter proxy settings (at least to my knowledge).

3) TapaTalk displays an error message and the "Processing" pop-up will spin forever. Just click on the screen and the app is fully functional. At worst this is just annoying. Once in a forum the issue is mute.

4) You need a rooted device and a file browser capable of mounting "/" root as RW (e.g. ES File Explorer)

* - the proxy app has ad-filtering capabilities but its not nearly as developed compared to other ad blocking solutions

Following these instructions I had this solution working, on my Nexus 10 (rooted Stock 4.2.2 and 4.3), in a matter of minutes. Make sure to remove or disable any other proxy (e.g. an ad blocker). If that is not done the proxies will clash and confuse your testing, especially when getting the proxy to auto start at boot time.

Change your WiFi proxy settings after installing the proxy server from the thread above. For Android 4.2.2/4.3 access your Settings->WiFi then long press your connection, click "Modify Network" on the pop-up. Check the "Show Advanced options". Then from "Proxy settings" select "Manual" and you can enter Proxy hostname "localhost", Proxy port "8118" and Bypass proxy for any URLs or IP addresses you want. I tried adding "xdaforums.com" but it did not make any difference with TapaTalk, so I'm not sure the Bypass values have any effect on the proxy server.

I found that when manually starting the proxy server and after changing the WiFi proxy settings that I needed to toggle WiFi off then on to get the connection to use the proxy server. That is not required when the proxy is started at boot time.

To have the proxy server start at boot time use a solution like the free "Universal Init.d" app, which even works with Android 4.3.

With a HTML color name chart you can easily change the defaults (black background, light grey text and green links) to any theme colors you wish. The Proxy uses a filter text file called "/data/opts/force_color.filters" which contains colors with the usual HTML color names (e.g. black, LightGray, LimeGreen ... etc). My one attempt at using HEX values (e.g. #000000 instead of "black") failed so I assume HEX values are unsupported.

I was pleasantly surprised that many of the news feeds in the Blacked out version of Flipboard suddenly displayed with the proxy's filter colors. Before that the detailed articles would display in the usual white background/black text somewhat reducing the value of a the blacked out theme.

Not all news feeds are effected though. For instance "Daily Beast" is completely altered while "The NewYorker" usually is unaffected. With "Slashdot" only the comments colors are changed. Still anytime you click for a "View Original Article", which launches a browser, you get the full Blackout proxy theme.

I hope those that are sick of being a user in the head-lights will enjoy this simple addition to the Blacked out theme efforts.

On a side note the linked thread mentions that Opera has a user style feature built-in and provides a Blacked out style sheet for download.