TITLE: Paper Frequencies — A Two-Ink Risograph Poster for a Zine Fair

PROMPT: Build a single-file, self-contained HTML page titled "Paper Frequencies — Risograph Zine Fair Poster": a print poster rendered in the browser with authentic risograph behaviour — two-ink overprint, halftone dots, misregistration, paper texture and crop marks. Palette: #f6f1e6 paper, #ff48b0 fluoro pink, #0078bf riso blue, #1a1a1a ink, #ffd400 accent. Typography: display system-ui 900 uppercase at clamp(38px,8.4vw,72px) with -.05em tracking and .86 line-height; body ui-monospace; heavy stencil feel. Structure: a warm grey desk background (#c7c0ae) with a fine woven noise built from two 1px repeating-linear-gradients plus a soft top light and a fixed vignette; a centred tilt wrapper containing an A-series poster (width min(92vw,650px), aspect-ratio 1/1.414, display:flex column, isolation:isolate) with paper background, deep drop shadow, and padding; inside the poster, two full-bleed ink layers and a procedural illustration. Ink layer A is a radial-gradient dot grid (11px pitch) in the current ink A colour masked by a 196deg linear gradient so it floods the top-left and fades out; ink layer B is a finer 7px dot grid in ink B masked by a radial gradient centred at 88% 8%. Both use mix-blend-mode: multiply so overlaps darken into a third colour, and both drift on a long alternating transform keyframe. The illustration is three elements: a halftone disc (radial-gradient dots, with a second finer blue dot layer masked to fade downward), a conic-gradient ring masked to an annulus, and a rotated repeating-linear-gradient band — all multiplied. Content sits above in a multiply-blended layer: a mono header row with a flex-grown hairline, the huge title "PAPER FREQUENCIES" with "FRE" in fluoro pink carrying a 2px blue offset shadow (simulated misregistration), a mono deck paragraph, a two-column definition list of date / venue / entry above a 2px rule, an imprint footer with two mono credit lines and a barcode built from 18 spans of varying widths, plus four corner crop marks, a registration target and a hidden roller element. Hovering the poster offsets the two ink layers in opposite directions by 3-4px to misregister the print. Clicking the poster (without dragging) cycles through four ink pairings by rewriting --a / --b / --c custom properties and fires a short scale kick. Dragging tilts the whole poster with perspective(1500px) rotateX/rotateY clamped to ±13/15 degrees and eases back to flat on release; touch-action is none so touch drag works. The PRINT button (and an automatic run 320ms after load) sweeps a skewed multiply-blended gradient roller across the poster via a transform keyframe while both ink layers nudge and settle, so the content is never hidden. All motion is disabled under prefers-reduced-motion, including the automatic roller run. All JS in one IIFE in a single inline <script> at the end of body; no external references; the substring "http" absent everywhere.

DESCRIPTION: A poster for a fictional zine fair, printed in the browser the way a risograph prints: two flat inks, overprinted, with visible halftone dots, slight misregistration and paper stock you can almost feel. The layout is blunt and confident — a giant stencil-weight title, a halftone sun-and-ring illustration bleeding through the type, a compact date and venue block, tiny print-shop credits, crop marks and a registration target at the edges. Hovering shoves the inks apart; clicking swaps the ink pairing; dragging tilts the sheet in your hands; PRINT runs a roller across it.

TECHNIQUES:
- Halftone dot grids as repeating radial-gradients at two pitches (11px and 7px) with per-layer mask-image gradients controlling where the ink floods
- mix-blend-mode: multiply over an isolated poster stacking context so pink and blue overprint into a third colour
- Offset-ink misregistration by translating the ink layers in opposite directions on hover, plus a hard 2px colour-offset text-shadow on the display title
- Simulated paper: layered 1px cross-hatch gradients, soft top light, desk vignette
- Procedural illustration from a halftone disc, a masked conic-gradient annulus and a rotated repeating-linear-gradient band
- Perspective pointer-drag tilt with clamping and eased release, pointer capture, and click-vs-drag discrimination by movement threshold
- Roller wipe as a skewed multiply-blended gradient bar animated with transform (content never hidden), auto-run on load and re-run from the PRINT button
- Crop marks, registration target, barcode built from spans, mono imprint footer; CSS custom-property ink pairs cycled from JS

INTERACTION: Hovering the poster pulls the two ink layers apart by a few pixels so the print looks misregistered; clicking the poster without dragging cycles through four ink pairings (pink+blue, blue+yellow, yellow+pink, pink+black) with a small scale kick; dragging the poster tilts it in 3D with perspective and eases back to flat when released; the PRINT button runs a roller wipe across the sheet, and the same wipe runs automatically once shortly after load. All of these are disabled or reduced under prefers-reduced-motion.