The product surface, organised by what the user does. Each feature below is in scope for MVP unless explicitly marked otherwise.

4.1 — Library

Users browse available artworks. Browsing affordances:

• Featured artworks
• New releases
• Categories
• Cultural themes
• Difficulty
• Free / premium status
• Downloaded / offline availability
• In‑progress / completed status

4.2 — Artwork detail

Each artwork displays:

• Title
• Preview image
• Category
• Difficulty
• Estimated completion time
• Region count
• Premium / free badge
• Download or play button
• Progress percentage (if started)
• Artist credit

4.3 — Downloads

Users download artwork bundles on demand. A bundle includes a manifest, region data, palette, preview, thumbnail, and optional line‑art reference. Once downloaded, an artwork is playable offline.

4.4 — Colouring canvas

The core canvas supports:

• Zoom and pan
• Tap‑to‑colour interaction
• Numbered region display
• Palette selection
• Correct / incorrect feedback
• Region fill persistence
• Progress calculation
• Smooth interaction on mid‑range devices

4.5 — Palette

The palette is the primary input device alongside the canvas. It displays numbered colours in the order they appear in the artwork, lets the user select the current colour, and shows per‑colour progress. Completed colours are dimmed and pushed to the end of the strip. An optional “highlight remaining regions” affordance fires a gentle pulse over unfilled cells matching the current colour.

4.6 — Progress tracking

The app tracks completed region IDs, completion percentage, last‑played and completed timestamps, the currently selected colour, the local sync state, and optionally time spent. Progress is local‑first and synced opportunistically when online.

4.7 — Monetisation

Decision (locked): Ochre & Soul launches with content packs as the only paid surface. A subscription tier is explicitly deferred to post‑MVP and is not implemented in Phase 4.

• Free starter artworks (every user gets these without paying)
• Premium content packs — one‑off purchases via the platform IAP (Apple StoreKit 2 / Google Billing 6+)
• Restore Purchases on every device
• No subscription, no rewarded ads, and no behavioural advertising at launch
• An ad‑supported free tier remains open as OD-01 and is not in MVP scope

Receipt validation and entitlement checks happen server‑side via Apple’s App Store Server API and Google Play Developer API. Family Sharing‑propagated entitlements are honoured (see §7.5).

4.8 — Admin and content management

Admin workflows support metadata creation, asset upload, validation, draft / published states, premium / free toggling, category and tag assignment, versioning, and an internal preview before publication.