# Progress Log

## Design Context

### Project Vision
Complete UI redesign of HCD Analysis tool. Modern, bold design with NHS color scheme inspiration (not constrained by it). Single-page dashboard replacing multi-page sidebar layout. Light mode only.

### Key Design Decisions
1. **No sidebar** — all filters in a prominent filter bar
2. **No user auth UI** — local app, no login needed
3. **Chart navigation via tabs** — top bar has chart type selection (Icicle now, more later)
4. **Instant filtering** — debounced (300ms), not "Apply" button
5. **Two date ranges**:
   - "Initiated" filter (default: OFF, include all patients)
   - "Last Seen" filter (default: ON, last 6 months)
   - "To" date always = latest date in dataset
6. **Searchable dropdowns** — Drugs, Indications, Directorates with search + counts
7. **Data source hidden** — SQLite only, refresh via CLI, show freshness indicator
8. **KPIs reactive** — update when filters change

### Color Palette (from DESIGN_SYSTEM.md)
- Heritage Blue: #003087 (deep, authoritative)
- Primary Blue: #0066CC (main actions)
- Vibrant Blue: #1E88E5 (highlights, hovers)
- Sky Blue: #4FC3F7 (accents)
- Pale Blue: #E3F2FD (backgrounds)
- Neutrals: Slate family (#1E293B → #F1F5F9)

### Typography
- Font: Inter (Google Fonts or system)
- Display: 32px/700, Heading1: 24px/600, Body: 14px/400, Caption: 12px/500

## Reflex Patterns

### Var operations in rx.foreach
When using `rx.foreach`, items are Reflex Vars. Use:
- `.to(int)` for numeric comparisons
- `.to_string()` for text operations
- Never use f-strings or Python operators directly

### Conditional rendering
Use `rx.cond(condition, true_value, false_value)` not Python `if`.

### State structure
- Event handlers modify state
- `@rx.var` decorated methods for computed/derived values
- All state vars need defaults

## Existing Codebase Reference

### Key files to reference
- `pathways_app/pathways_app.py` — existing Reflex app (2100+ lines)
- `analysis/pathway_analyzer.py` — chart data preparation logic
- `data_processing/loader.py` — SQLite data loading
- `core/models.py` — AnalysisFilters dataclass

### Patterns that work in existing code
- `State` class with filter variables
- `rx.plotly()` for chart rendering
- Multi-select with `rx.checkbox` groups
- Theme configuration via `rx.theme()`

## Iteration Log
<!-- Each iteration appends a structured entry below. See RALPH_PROMPT.md for format. -->