# NEXT Athlete OS RC101 — S2P1 transparent premium assets

## Scope

Built from RC100. Converts the approved Stage-2-Phase-1 premium illustrations from baked studio composites into transparent foreground assets that can be layered over selectable theme backgrounds.

## What changed

- Added `assets/img/exercises/premium/s2p1/source/` with original approved composite source images.
- Added `assets/img/exercises/premium/s2p1/cutout/` with 31 transparent foreground WebP assets.
- Updated `assets/js/core/exercise-illustrations.js` so S2P1 premium entries use:
  - `foreground`
  - `source`
  - `transparent: true`
  - `backgroundMode: 'theme-layered'`
  - theme-specific backgrounds for neutral, athlete, hockey and downhill.
- Updated background references to existing SVG background files under `assets/img/exercise-backgrounds/v98/`.
- Updated illustration service storage key to RC101.
- Added RC101 CSS for transparent foreground layering and foreground drop-shadow.

## Asset model

```txt
source/original = approved AI exercise image
cutout/foreground = athlete + equipment + arrows, transparent background
background = selected theme layer in app
```

## Known QA note

The foreground cutouts are generated from existing non-transparent images, so the transparency is a practical first-pass extraction. It is good enough to validate app layering and theme behavior, but individual assets can still be manually refined later if edge quality around white shoes/socks or pale objects needs polish.

## QA screenshots

- `qa_screenshots/rc101_s2p1_transparent_mobile_390x844.png`
- `qa_screenshots/rc101_s2p1_transparent_ipad_820x1180.png`
- `qa_screenshots/rc101_s2p1_transparent_desktop_1440x1024.png`

Screenshots were produced with a deterministic static PIL composition fallback, not Chromium.