Simply hit the Pocket button on your desktop browser or visit the sharing menu from your mobile browser to save an article.
And sure enough, the app offers a toggle to use 'true black' for articles and the menus.
The premise is pretty simple in case you haven't heard, as you can buy and download millions of ebooks for use within the app.
Now, about bringing this option to the rest of the app...
One of the most popular third-party Reddit apps, Sync for Reddit was around long before the website decided to make its own official Android app.
The app has a ton of features, ranging from multiple account support and offline synchronization to fully customizable themes.