The phrase "to contrast the colors" means to create a visual difference between two or more colors by placing them next to each other in such a way that their differences are emphasized. This can be done through various methods, including using different shades, tones, and hues of the same color family, as well as using complementary colors (colors opposite each other on the color wheel). Contrasting colors is an important design principle used in graphic design, fashion, interior decoration, and many other fields to create visual interest, draw attention to specific elements, and make a statement.