macOS Mojave's "dark mode" can be enabled for Gridsync by setting NSRequiresAquaSystemAppearance to False in the .app bundle's Info.plist file (or, alternatively, by running the application "directly" from python source) after turning on the feature in macOS' System Preferences -> General. Currently, however, some stylesheets set within the application use colors that can reduce legibility against a dark background (particularly for grey-ish text). Accordingly, these UI elements or the logic adjacent to them should be updated to use a more appropriate color palette when macOS dark mode is enabled (or, perhaps, alternatively, if theme-detection proves difficult, Gridsync could provide its own dark mode to ensure stronger consistency across the application).