Is it permissible for a woman observing 'iddah to change the color of grey hair?

It is not permissible for a woman observing the 'iddah (waiting period) after her husband's death to change the color of the gray hairs in her head, as this is considered an adornment forbidden during the mourning period. The Prophet, peace and blessings be upon him, forbade the woman whose husband had died from adornment, such as wearing garments dyed with 'usfur (safflower) or dyed red (mumashshaq), jewelry, dyeing (khidab), and kohl. Scholars have agreed that dyeing is included in the forbidden adornment, and this encompasses henna and changing hair color.