docs: add first principles and mind mapping results to brainstorming session

bmad/_bmad-output/brainstorming/brainstorming-session-2026-04-12-001.md

@@ -1,5 +1,5 @@
 ---
-stepsCompleted: [1, 2]
+stepsCompleted: [1, 2, 3]
 inputDocuments: []
 session_topic: 'Classic 2048 web game recreation'
 session_goals: 'Faithful recreation of original 2048 gameplay with local scoring, built as exploration project'
@@ -7,6 +7,7 @@ selected_approach: 'user-selected'
 techniques_used: ['First Principles Thinking', 'Mind Mapping', 'Morphological Analysis']
 ideas_generated: []
 context_file: ''
+techniques_completed: ['First Principles Thinking', 'Mind Mapping']
 ---
 
 # Brainstorming Session Results
@@ -35,3 +36,75 @@ context_file: ''
 - Morphological Analysis: Systematically explore tech stack and architecture decisions
 
 **Selection Rationale:** Practical, implementation-focused techniques suited to a well-defined recreation project
+
+## Technique Execution Results
+
+### First Principles Thinking
+
+**Core Mechanics Researched (from original source code by Gabriele Cirulli):**
+
+- **Grid:** 4x4, cells[x][y], (0,0) = top-left
+- **Tile Spawning:** 2 tiles at start, 1 after each valid move; 90% chance of 2, 10% chance of 4; random empty cell
+- **Movement:** 4 directions (Up/Down/Left/Right); tiles slide as far as possible
+- **Merging:** Same-value tiles merge (doubled); each tile merges only once per move; leading-edge order
+  - [2,2,2,2] left → [4,4,_,_] (+8)
+  - [2,2,4,4] left → [4,8,_,_] (+12)
+- **Scoring:** Each merge adds new tile value; best score in localStorage
+- **Win:** Creating a 2048 tile; can continue with "Keep going"
+- **Game Over:** No empty cells AND no adjacent same-value tiles
+- **State:** Full game state saved to localStorage after every move; cleared on game over
+
+**Visual Design:**
+- Background: #faf8ef, Grid: #bbada0, 15px spacing
+- Tile colors: 12 tiers from #eee4da (2) to near-black (>2048)
+- Dark text (#776E65) for 2/4, bright text (#f9f6f2) for 8+
+- Glow effects on 128+ tiles
+- Font: 55px default, 45px for 100+, 35px for 1000+
+
+**Animations:**
+- Slide: 100ms ease-in-out CSS transform
+- New tile pop: 200ms scale(0→1), delayed 100ms
+- Merge bounce: 200ms scale(0→1.2→1), delayed 100ms
+- Score "+N": 600ms float up + fade
+- Win/Lose overlay: 800ms fade in, delayed 1200ms
+
+**Input:**
+- Keyboard: arrows, WASD, Vim (hjkl), R to restart
+- Touch: single-finger swipe, 10px threshold
+- Modifiers ignored
+
+### Mind Mapping
+
+**Component Breakdown:**
+
+```
+                              2048 GAME
+                                 │
+        ┌────────────┬───────────┼───────────┬────────────┐
+        │            │           │           │            │
+   GAME LOGIC    RENDERING    INPUT       UI/UX       INFRA
+        │            │           │           │            │
+   ┌────┴────┐   ┌───┴───┐  ┌───┴───┐  ┌───┴───┐   ┌───┴───┐
+   │         │   │       │  │       │  │       │   │       │
+  Grid    Score  Tiles  Anim Keyboard Score   Win/ State  Build/
+  State  System  Draw   ations  ↕    Display Lose Persist Deploy
+   │         │   │       │  Swipe    Best   Overlay localStorage
+   │         │   │       │  Touch    Score  Messages
+  4x4     Merge  Colors  Slide      New Game
+  Cells   Value  Fonts   Pop        Button
+  Empty   Best   Sizes   Bounce
+  Check   Score  Glow    Fade
+  Spawn
+  Move
+  Merge
+  GameOver
+  Win
+```
+
+**6 Key Component Groups:**
+1. Game Logic — Grid state, spawning, sliding, merging, game over/win detection
+2. Rendering — Grid draw, tile colors (12 tiers), font sizing, glow effects
+3. Animations — Slide, pop, bounce, score float, overlay fade
+4. Input — Keyboard (3 schemes), touch/swipe, modifier blocking, restart
+5. UI/UX — Score displays, buttons, overlays, intro text, responsive layout
+6. Infrastructure — localStorage persistence, responsive (500px/280px), build & deploy