Build a Kanban project management board using HTML5, CSS3, and JavaScript. Create a flexible board layout with customizable columns (To Do, In Progress, Done, etc.). Implement drag-and-drop card movement between columns with smooth animations. Add card creation with rich text formatting, labels, due dates, and priority levels. Include user assignment with avatars and filtering by assignee. Implement card comments and activity history. Add board customization with column reordering and color themes. Support multiple boards with quick switching. Implement data persistence using localStorage with export/import functionality. Create a responsive design that adapts to different screen sizes. Add keyboard shortcuts for common actions.