Suit wear: three-color principle, three-one law and three taboos: Three-color principle, suits, shirts, ties, leather shoes, handkerchiefs, socks, etc. should not exceed three colors. "Little three colors": The colors of watch straps, belts, and leather shoes should be consistent, or at least belong to the same color series. The Trinity Law: In business activities, celebrations, signing ceremonies and other occasions, the "three parts" of "shoes, belt, briefcase" should be kept in one color (black) to reflect "status and identity". Three taboos: 1. When wearing a suit, the left sleeve trademark Not removed 2. Wrong wearing socks: nylon stockings, silk stockings, white socks are not worn 3. Wrong way of wearing ties