# Casefile Investigator: Operation Oceanus

Create an interactive, single-file HTML evidence wall and caseboard investigator.

## Theme
Maritime disappearance of the research vessel "Oceanus".

## Core Systems
1. **Evidence Wall:** A 2D workspace containing pinned items (clues).
2. **Evidence Types:** 
   - Documents (Manifests, internal memos)
   - Transcripts (Witness notes, radio logs)
   - Data (Sonar logs, coordinate maps)
3. **Connections:** Visual "red string" connections between related evidence items using SVG lines.
4. **Detail Pane:** Clicking an item on the board opens a focused reading pane with the full content of the clue.
5. **Timeline/Progress:** The investigator must uncover links between clues by reading details. "Insights" are unlocked by interacting with clues. State progress is tracked (e.g., Uncovered: 0 / 5).

## Visual Direction
- Dark, gritty, archival texture (dark greys, corkboard elements, faded paper colors).
- Typewriter fonts for transcripts, official-looking sans-serif for documents.
- Messy but readable layout, mimicking an investigator's board.
- Smooth transitions when opening the detail pane.
- Mobile-responsive: Use a standard flex/grid layout or a pannable canvas for desktop, and a vertical list/stacked cards view for mobile.

## Technical Constraints
- Single `index.html` file containing all HTML, CSS, and vanilla JS.
- No external images (use CSS or SVG).
- Vanilla JavaScript for state and interactions.