Build your own Acrobat.

# Build an original app inspired by Acrobat

You are an experienced product designer and full-stack engineer. Build a working, polished MVP from the brief below. Implement the core journeys end to end; a static mockup is not sufficient. Inspect the current environment, make sensible implementation decisions, and get started. Ask a question only if a missing answer genuinely blocks implementation.

Starting platform: Desktop. Explicit customized Product & audience and Tech stack requirements take precedence over this starting target.

## Product & audience
Build an original PDF toolkit called Paperdesk, inspired by Acrobat. It is for individuals reading and organizing their own PDFs. The main flow is opening a document, navigating pages, annotating it or organizing its pages, and saving a verified output. Scope the first version to existing PDF content rather than arbitrary word-processor-style editing.

## Design
Use an original desktop document viewer with page thumbnails, a central zoomable page, a compact annotation toolbar, and a properties panel. Make page selection, unsaved state, save-as destination, and unsupported document features visible. Offer keyboard navigation and readable zoom controls.

## Features
1. Viewer: open supported PDFs, show page thumbnails, navigate and zoom, search extractable text, and display document metadata. Detect encrypted or unsupported documents with a useful message.

2. Page operations: reorder, rotate, extract, delete, and merge pages from user-selected PDFs. Preview changes, provide undo, and write to a new file by default.

3. Annotations: add highlights when text coordinates are available, notes, and free-text boxes; edit/remove app-supported annotations and preserve existing supported annotations.

4. Forms: fill supported existing AcroForm text and checkbox fields, validate required fields where specified, and save values. Do not imply support for every dynamic form or signature workflow.

5. Output: export the modified PDF and verify page count, ordering, text, and form values by reopening it. Support image export for selected pages and handle save permission errors.

## Tech stack
Use Python and PySide6 for a new desktop app with a maintained PDF renderer/writer whose licensing fits the project. Evaluate the supported document features before choosing the engine and bundle required notices. Separate rendering, document transformations, and UI state; perform expensive work in a worker. Disable PDF JavaScript and avoid unsafe external actions. Do not implement cryptographic signatures or security-sensitive redaction as visual overlays.

## Data & behavior
DocumentSession {id, sourcePath, hash, pageOrder, dirty}; PageRef {sourceDocumentId, sourceIndex, rotation}; Annotation {pageId, type, bounds, text, color}; FormValue {fieldName, type, value}; OperationHistory; ExportJob. Preserve source files, use temporary output followed by a safe rename, and explicitly report unsupported features that cannot be retained.

Acceptance checks and scope:
Test merging two PDFs, page reorder and rotation, text search, annotation round-trip, form save/reopen, encrypted input, and failed output writes. Confirm originals are unchanged. Exclude OCR, arbitrary text reflow, certified signatures, security redaction, and full fidelity for unsupported XFA or specialized PDF features.

## Originality and assets
The named product is a reference for general workflows only. Use an original product name, visual identity, wording, layout, and assets. Do not copy proprietary code, branded logos, distinctive screens, private APIs, paid templates, or protected media. Use original or appropriately licensed sample data and assets. Build from this brief rather than scraping the reference service. Do not imply affiliation with the referenced company.

## Implementation quality
- Make every visible control work, with clear loading, success, empty, validation, and failure states. Remove controls for unimplemented features.
- Support the target platform and responsive or resizable layouts where appropriate. Use platform-appropriate accessibility semantics, labels, keyboard operation, visible focus, sufficient contrast, and reduced-motion preferences. Provide alternatives for drag-only interactions.
- Validate inputs at the relevant boundary. Treat imported or user-generated content as untrusted; render it safely. Confirm destructive actions or offer undo.
- Keep state changes reliable across navigation and reloads. Never silently lose edits. Handle persistence and network errors with an actionable message.
- Keep the scope realistic. Prioritize the complete primary journey. If a custom Features section differs from the baseline, update the data model, design, and acceptance checks to match it; explicit custom requirements take precedence over baseline assumptions.
- Provide realistic original sample content and a useful empty state. Keep sample data clearly separate from user-created data.

## Delivery and verification
1. Inspect the repository and outline the implementation in a few sentences.
2. Implement the app and connect its actual data flow. Continue until the primary journey works.
3. Run appropriate checks and test the acceptance cases above on the target platform. Verify responsive layouts and keyboard navigation when browser tools are available. For native projects, build with the available SDK and test an emulator or device when possible; report any missing native verification honestly. For games, verify the rules and gameplay loop, not only the menus.
4. Fix observed failures, then provide the runnable result, setup/run instructions, a brief explanation of what is implemented, and any specific configuration or verification limits.

This is a focused MVP. Do not add billing, AI services, or unrelated features unless explicitly requested in the brief. Start building now.