Create one standalone premium abstract textured background image for web design. No text, no letters, no interface, no logos, no watermark, no border, no collage. Full bleed. Tactile irregular stochastic grain integrated into the colors, not a visible repeating pattern. Keep useful quiet negative space for website copy. Landscape 16:9. Extremely fine silver and charcoal film grain on a very dark graphite ground, an almost imperceptible cool white mist of light in the lower right third. Pure minimal texture with no large objects or shapes. Subtle low-contrast photographic grain suitable beneath white text. Fine enough to feel sophisticated, visible at full resolution, no stars or glitter.