Each theme file can contain multiple themes—such as light and dark variants—under the same theme family. , "themes" : [ { "name" : "My Cool Dark Theme" , "appearance" : "dark" , "style" : { "editor.background" : "#000" // ... } }, { "name" : "My Cool Light Theme" , "appearance" : "light" , "style" : { "editor.background" : "#fff" // ... } } ] } Add a theme file to the themes directory and it will be available in the theme selector the next time Zed loads.