Sun Tzu Page 1761 -

*Hover/ tap a line → highlighted overlay on scan + footnote numbers appear.* *Click a highlighted term → tooltip with definition, cross‑refs, and “Add Note”.* | Layer | Technology | Notes | |-------|------------|-------| | Front‑end | React / Next.js + TypeScript | Component‑driven UI; server‑side rendering for SEO. | | | CSS‑Modules or TailwindCSS | Rapid responsive styling. | | | PDF.js (for displaying scan) | Allows zoom and line‑highlight overlay. | | Back‑end | Node.js + Express (or Django) | API for fetching scan, OCR text, annotations. | | | PostgreSQL + PostGIS (optional) | Store pages, annotations, user comments. | | | ElasticSearch | Full‑text search across all editions. | | OCR & Alignment | Tesseract OCR (trained on classical Chinese fonts) | Generates line‑by‑line text. | | | Custom alignment script (Python) | Maps OCR lines to image coordinates. | | Audio | AWS Polly (Mandarin‑Chinese, English) or Azure Speech | Generates TTS on‑the‑fly, cached per page. | | Collaboration | WebSockets (Socket.io) | Real‑time comment updates. | | Accessibility | axe‑core, ARIA guidelines | Automated testing for WCAG 2.1 AA. | | Deployment | Vercel (frontend) + AWS RDS (DB) + S3 (scans) | Scalable and cost‑effective. | 7. Data Model (simplified) -- Page CREATE TABLE pages ( id SERIAL PRIMARY KEY, edition_id INT REFERENCES editions(id), page_number INT, image_url TEXT, ocr_text TEXT, created_at TIMESTAMP DEFAULT NOW() );

-- Concept tag CREATE TABLE concept_tags ( id SERIAL PRIMARY KEY, page_id INT REFERENCES pages(id), line_number INT, term VARCHAR(64), definition TEXT, related_passages JSONB ); Sun Tzu Page 1761

-- Annotation (footnote, commentary) CREATE TABLE annotations ( id SERIAL PRIMARY KEY, page_id INT REFERENCES pages(id), line_number INT, content TEXT, author_id INT, created_at TIMESTAMP DEFAULT NOW() ); *Hover/ tap a line → highlighted overlay on