Color combination of red and blue

Quick answer：

The color combination of red and blue is often used in various contexts due to its striking contrast. In design, it can evoke a range of emotions from energy and warmth to tension and conflict. In nature, the combination is found in various species, such as the red and blue flowers of the lupine plant. Historically, red and blue have been associated with different cultural meanings, such as power and loyalty in Western cultures and the sky and water in Eastern philosophies.