Hair color design is an art that involves selecting the right color to complement one's facial features. The right color can enhance facial contours and bring out the best features. Factors such as skin tone, hair texture, and facial shape are considered. Facial shapes include oval, round, square, heart-shaped, and diamond-shaped. Each shape may require different color techniques to balance and highlight features. Matching hair color with facial shape is important for achieving a harmonious and attractive look.