Synonyms that are in the dictionary are marked in green. Synonyms that are not in the dictionary are marked in red.
Antonyms that are in the dictionary are marked in green. Antonyms that are not in the dictionary are marked in red.
If you want a more granular level of control over your keyboard lighting, you can do so by going into System Preferences > Keyboard > Adjust Keyboard Brightness in Low Light.
Source: https://www.devicemag.com/how-to-turn-down-keyboard-brightness/