The Hebrew word for light-colored or bright is בהיר
As for dark-colored, it’s כהה
She likes dark-blue flowers (flowers of the color dark blue).
Likewise, dark skin is עור כהה
Your (a male’s) skin is darker than mine.
Now, כהה means dark when speaking about a color. If you’re talking about a dark room or forest, the word is חשוך
It’s dark (in) here.