What is the ruling on dyeing part of the eyebrows to make them appear thinner, and does this take the ruling of plucking (al-nams), knowing that the purpose is to adorn oneself for the husband?

Coloring eyebrows does not fall under the prohibited plucking (namṣ), but rather it is a form of dyeing hair which is permissible, provided that the disliked black color is avoided, based on the saying of the Prophet, peace and blessings be upon him: "Change its color, but avoid black."