It appears Apple may be working to expand the Dark Mode feature for macOS. Introduced with Yosemite, OS X Dark Mode changes the appearance of just the Dock and menubar to a black translucent style rather than white/silver.

A developer/hacker on Twitter has seemingly found a way to activate a more comprehensive dark appearance for some system apps such as Safari or System Preferences, as pictured. It’s unclear what method or technique the developer is using to activate this and there’s no indication that this headed to public release anytime soon.

Alongside these new screenshots from macOS, other developers have previously found similar app-level support for ‘real’ Dark Mode in iOS 10. It appears Apple is at least testing the feature internally. None of the leaks to date have shown an implementation that seems close to being finished, not even close.

Adding Dark Mode system-wide is a huge undertaking and should not be taken lightly. Despite these images, it is very unlikely Apple is sitting on the feature for a surprise announcement later in the year. The most optimistic perspective for Dark Mode fans is that this signals Apple is working on Dark Mode for future iterations of iOS and macOS.

Speculating, Apple may be readying Dark Mode for the iPhone 8 … which is expected to include an OLED screen best suited for displaying dark content. Apple Watch uses this exact strategy featuring a black interface to take full advantage of OLED’s contrast levels and power efficiency when displaying dark pixels. It could also appear later in the development cycle for iOS 10 and macOS Sierra, similar to how major features like Night Shift appeared mid-way through iOS 9 with the iOS 9.3 update.

For now though, it is doubtful that Dark Mode will appear in any form on iOS 10 or on Sierra (beyond what is already possible with the dark appearance for Dock and menubar).