This is already going to be a feature in the new Subeta. If you check out here which is the V2 version of the site that slowly features are being moved to, you will see the little sun/moon icon and change theme in the menu.It is a day/night mode. For desktop you have to click on your HA headshot. For mobile please see Screenshots in next post. So because of that I doubt anything official will be applied to the current site. You can also use this: -Night Mode- Shengui Guo Custom CSS [v2.0]