The project is a browser canvas mini-game titled “Goat Giggle Simulator.” The existing stack is plain HTML, CSS, and JavaScript using ES modules, with game logic separated across `src/state.js`, `src/input.js`, `src/update.js`, `src/render.js`, `src/game.js`, and `src/main.js`. Existing work includes a canvas-oriented game state, input handling, update logic, procedural rendering, and a stylesheet, plus a design reference at `docs/design-reference.png`. The README describes a sunny pasture game where the player controls a goat, collects apples, headbutts props, and earns points, with HUD, instructions, reset/replay, particles, screen shake, and impact labels as intended features. Preserve the current module structure and cheerful procedural-shape visual direction rather than replacing it with external art. The supplied files do not include a preview of the running page or evidence that the code was executed, so do not assume the game is complete, wired, runnable, or visually matched. Verify that `index.html` loads `src/main.js`, that `main.js` creates the renderer/game loop, and that update/render/input interactions are connected. Check for missing browser event-loop setup, canvas sizing, reset behavior, collision/objective completion, and responsive layout before extending the design. The main blocker is verification: no generated-code execution or live interaction preview is supplied.

## Visual handoff
VISUAL HANDOFF:
- Design reference: `docs/design-reference.png`. It is non-authoritative visual guidance; the user prompt and runnable target remain authoritative.
- Design brief: A playful, colorful browser goat-simulator mini-game set in a sunny farm meadow. Use the existing canvas-game module structure and procedural shapes/colors rather than external art. The player controls a mischievous goat, explores a bounded pasture, headbutts props, collects apples, and earns points. Keep the interface readable and cheerful: responsive canvas, compact score/objective HUD, movement instructions, and a reset/replay control. Give impacts satisfying visual feedback with particles, screen shake, and brief labels such as “BONK!” or “MUNCH!”.