Retro poster prompt

Design a finished poster in portrait format. Headline: "The Long Run". Subtitle: "City half marathon". Include these details as legible text: Sunday, April 21 · 7 am start Visual style: Retro. Colors: cobalt and white. Visual direction: a runner's shadow stretched across an empty morning bridge Clear typographic hierarchy. Spell all text exactly as given and add no other text. The poster fills the whole image edge to edge: no mockup, frame, wall or surrounding scene. 1960s to 70s screen-print poster, halftone grain, slightly misregistered inks, rounded display type Generous negative space. Warm off-white paper with subtle fibers and grain. Limit the palette to the colors named and the paper, nothing else. Halftone dots thinning out, slight misregistration, uneven inking, visible paper grain, no digital gradients or blur. No watermark, no logo, no signature, no border. AVOID: no digital gradients, no glossy 3D, no photoreal background, no clip-art look, no cheap retro filter, no template feel, no text beyond what is specified