Serene Abstract Blue Gradient Background

abstract blue gradient background, soft pastel sky blue tones blending into white, subtle diagonal sweeping bands of light and shadow, grainy textured surface resembling spray paint or chalk pastel on paper, gentle vignette with deeper navy blue in lower corners, smooth diffused light source in upper center creating a bright luminous glow, no subject, minimalist abstract art, fine grain noise texture overlay, serene and airy atmosphere