If the above methods don't work for you, you can try using an external solution.
Before we hunt for a "link," we must address the elephant in the room. adobe flash cs6 dark mode link
Adobe Flash Professional CS6 does not feature a built-in, comprehensive dark mode interface like modern Adobe CC applications. While some Adobe CS6 apps (like Photoshop and Illustrator) offered interface color adjustments in Preferences, Flash CS6 generally retains a light-grey theme. If the above methods don't work for you,