diff --git a/docs/superpowers/specs/2026-06-30-matrix-live-style-variation-design.md b/docs/superpowers/specs/2026-06-30-matrix-live-style-variation-design.md
new file mode 100644
index 0000000..48707bc
--- /dev/null
+++ b/docs/superpowers/specs/2026-06-30-matrix-live-style-variation-design.md
@@ -0,0 +1,95 @@
+# Matrix `_live` per-style variation (full loop that breathes)
+
+**Date**: 2026-06-30
+**Status**: design approved, pending plan
+**Scope**: `sound_algo/data_only/matrix_presets/generate_presets.py` + `test_sections.py` + regenerated `*.matrix`. Refinement of the `_live` continuous loop.
+
+## Context
+
+`make_live_continuous` tiles the plateau across all 64 bars, so the `_live`
+loop is four identical 16-bar blocks (133/133/133/133 on techno_drive) — full
+but static. The user wants variation in the live loop, **adapted to each style**
+(per genre), while staying full (no voice drops, no intro/breakdown — those
+were the point of the previous fix).
+
+## Decision (from brainstorming)
+
+Keep full density; add per-style variation by **recolouring active cells** (the
+matrix colour 1-6 system changes the pattern a voice plays without removing it)
++ **phrase-end fills**. The variation profile is keyed to the morceau's style.
+
+## Design
+
+### Style derivation — `LIVE_STYLE` (generate_presets.py)
+Explicit morceau -> style map (7 groups), default `"techno"`:
+- **techno**: techno_drive, detroit_soul, peak_drop, rave_stab, acid_journey
+- **psy**: dub_techno, psytrance_roll, minimal_hypno, hypnotic_arp
+- **trance**: trance_euphoria, melodic_builder, melodic_deep, progressive_lift, synthwave_drive
+- **breaks**: breakbeat, bass_science, jungle_amen, dnb_roller, footwork_chop, neuro_reese, tribal_perc
+- **electro**: electro_808, ebm_body, electro_funk
+- **industrial**: schranz_drive, industrial_grind, hardcore_punk
+- **ambient**: ambient_intro
+
+### Variation profiles — `LIVE_VAR`
+Per style: `busy` voices recoloured in `busy_blocks` (16-bar block indices 0-3)
+to `busy_color`; `fill` voices' active cells set to colour 6 on the last 2 bars
+of every block. Colours chosen per voice kind — rhythmic voices use 2 (busier)
+or 4 (double-time); melodic voices use 3 (octave-up lift), since step-mode
+ignores stretch so 2/4 are inaudible on melodic voices.
+
+| style | busy voices | busy_blocks | busy_color | fill voices |
+|-------|-------------|-------------|-----------|-------------|
+| techno | hats, perc | 1, 3 | 4 (double) | snare, clap, perc |
+| psy | acid, arp, reese | 1, 3 | 3 (octave) | perc |
+| trance | arp, lead | 2 | 3 (octave) | snare, clap |
+| breaks | snare, shaker | 1, 3 | 2 (busier) | snare, perc, tom |
+| electro | hats, clap | 1, 3 | 2 (busier) | clap, perc |
+| industrial | perc, tom | 1, 3 | 2 (busier) | kick, perc, tom |
+| ambient | bells, melody | 2 | 3 (octave) | (none) |
+
+### `make_live_continuous(g, style="techno")`
+1. Tile the plateau (existing).
+2. `_live_variation(g, style)`:
+   ```python
+   def _live_variation(g, style):
+       prof = LIVE_VAR.get(style, LIVE_VAR["techno"])
+       for blk in prof["busy_blocks"]:
+           for v in prof["busy"]:
+               vi = VI[v]
+               for b in range(blk*16, blk*16+16):
+                   if g[vi][b] > 0: g[vi][b] = prof["busy_color"]
+       for blk in range(BARS // 16):
+           for v in prof["fill"]:
+               vi = VI[v]
+               for b in (blk*16+14, blk*16+15):
+                   if g[vi][b] > 0: g[vi][b] = 6
+       return g
+   ```
+   Only recolours active (`> 0`) cells -> density unchanged, voices never dropped.
+
+### Wiring
+- `main()`: `post = (lambda g: make_live_continuous(g, LIVE_STYLE.get(name, "techno")))
+  if sec == "live" else None`.
+- `test_sections.grid_of`: `G.make_live_continuous(g, G.LIVE_STYLE.get(name, "techno"))`.
+
+## Testing
+
+- **`test_sections.py`**: the density asserts (live full-from-start, no breakdown
+  dip, live densest) STILL hold — recolouring keeps cells non-zero. NEW: assert
+  the live is not four identical blocks (variation present) for every morceau
+  except the ones whose profile is genuinely minimal — i.e. the live's 4 blocks
+  are not all byte-equal (`len({tuple(row[i*16:i*16+16]) ...}) > 1` for some voice).
+- **SC**: `validate_presets.scd` -> 84/84 + DEFAULTS PASS (cells only recoloured;
+  mods/poses/instruments untouched). Deterministic regen.
+- **Live smoke**: reload several `_live` of different genres -> each loops full but
+  evolves in a style-appropriate way (techno double-time hats + fills; breaks
+  snare rolls; ambient gentle bell octaves; etc.); intro/outro unchanged.
+
+## Out of scope
+
+- Per-morceau (vs per-style) bespoke variation; new voices; intro/outro changes.
+
+## Decided defaults
+
+- 7 style profiles; recolour-active + phrase-fills; full density preserved.
+- Rhythmic busy -> colour 2/4, melodic busy -> colour 3.