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. Square 1:1. Large angular chartreuse yellow-green wedges slice diagonally through the right half and lower edge of a graphite black composition. Vivid coarse screenprinted noise and uneven ink density, a few tiny off-white flecks embedded in pigment, no stars. Left upper half calm dark space. Confident Swiss modernist geometric artwork, sharp shapes with grainy surfaces, no text or symbols.