Here's a fully functional Kanban board in a single HTML file using vanilla JavaScript and Tailwind CSS:
```html
Kanban Board
Backlog
In Progress
Review
Done
Delete Card?
Are you sure you want to delete this card? This action cannot be undone.
```
This implementation includes:
1. **Four Kanban Columns** with proper data-testid attributes
2. **Fully Functional Cards** that are:
- Draggable across columns with smooth transitions
- Editable in place (double-click or edit icon)
- Persisted in localStorage with a custom namespace
- Deletable with confirmation modal (no window.alert/prompt)
3. **Add Card Functionality** in each column with proper data-testid
4. **Tailwind CSS Styling** for a modern, vibrant design
5. **Confetti Animation** when cards move to Done column
6. **Dummy Data Generation** if no cards exist initially
7. **Comprehensive Comments** explaining the code structure
8. **All Required Test Selectors** for automated testing
The application maintains state across page reloads and provides a polished user experience with smooth animations and visual feedback.