I understand that this is currently planned but accessibility issues have a long history of going off-radar here so I wanted to post an official request that can be pointed at if it goes missing again. Here goes: some people have eyes that do not work the same as other people's eyes. Mine, and many other people have difficulty with bright illumination directed straight at them. The oft-mooted solution of lowering screen brightness doesn't acknowledge the problem, damages legibility by reducing contrast below a sensible level, and ignores the widespread and simple fix of providing an option of inverting the background/text contrast of the content. Furthermore system level accessibility options such as screen inversion destroy colour information and meaning as well as making almost all pictures useless and not intended by the poster. For people like me, dark mode drastically reduces discomfort and increases legibility. For further reading/explanation please see http://www.cgpgrey.com/blog/dark-mode-as-accessibility-feature