Dark blue background has several purposes: 1. Evoking Calmness and Trust: Dark blue is associated with calmness, stability, and trust, making it ideal for creating a soothing atmosphere. 2. Professionalism and Authority: It conveys a sense of professionalism, expertise, and competence, which is why it is often used by financial institutions, consulting firms, and other businesses. 3. Contrast and Readability: Dark blue backgrounds provide good contrast for text and images, enhancing readability, especially when combined with light-colored fonts. 4. Aesthetic Appeal: Dark blue backgrounds are visually appealing and versatile, complementing a variety of other colors and design styles. 5. Technological and Luxury Impression: In design, dark blue can make technology and electronic products seem cutting-edge and luxurious.