However, if you must stick to CS6 (for legacy plugins, specific ActionScript 2.0 needs, or preference), will give you the visual dark mode you want, provided you remember to toggle it off before exporting your final animations.
Make sure the application is completely shut down. adobe flash cs6 dark mode
To change the actual stage (artboard) color, go to Modify → Document and set the Stage color to #2b2b2b . However, if you must stick to CS6 (for