Harmonious colors

Quick answer：

Harmonious colors refer to a color scheme in which colors are selected to create a visually pleasing and balanced combination. This typically involves using colors that are either complementary, analogous, or triadic. Complementary colors are those opposite each other on the color wheel, such as blue and orange. Analogous colors are those next to each other on the color wheel, like red, orange, and yellow. Triadic colors are evenly spaced around the color wheel, like red, green, and blue.