Here is a **fully functional Kanban board** built with vanilla JavaScript, including all requirements and proper namespacing, persistent storage, animations, and a modern vibrant look. You can copy-paste the entire code into a `.html` file for immediate testing.
```html
Kanban Board
>
```
---
### Features Covered:
- **Frameworks:** Vanilla JS only, no frameworks.
- **Columns:** Backlog, In Progress, Review, Done (with unique keys).
- **Editable cards:** Double-click for in-place edit; Enter edits and saves.
- **Drag & Drop:** Cards move between columns and stay in place otherwise.
- **LocalStorage:** State survives page reloads, persisted with a unique key in `localStorage`.
- **Delete:** Card confirmation dialog (no external libs) and standard delete.
- **Confetti:** Lightweight animated confetti on card addition (via CSS keyframes).
- **Modern, vibrant UI** with Tailwind CDN and custom transitions.
- **Thoroughly commented** for clarity and maintainability.
You can save this as `kanban.html` and open with a modern browser to see it fully working. Enjoy!