Comment System

# Comment System PRD

## Overview
Build a threaded comment system that supports nested replies, voting, moderation controls, and markdown formatting, all persisted to localStorage.

## Requirements
- Add top-level comments with text content and a display name
- Threaded replies nested up to 5 levels deep
- Upvote and downvote per comment with net score display
- Sort comments by newest, oldest, or top voted
- Edit own comments after posting
- Delete own comments (show [deleted] placeholder if the comment has replies)
- Markdown support in comments (bold, italic, inline code, links)
- Relative timestamps displayed on each comment (e.g., "2 min ago", "3 hours ago")
- Collapse and expand individual threads
- Character limit of 2000 characters with a live counter
- Reply indicator showing "replying to @user" when composing a reply
- Permalink for each comment (anchor link or URL hash)
- Report comment button with a reason selector
- Load more replies button for deeply nested threads
- Author highlight to visually distinguish the original poster
- Persist all comments, votes, and state to localStorage

## Tech Stack
- HTML, CSS, JavaScript (vanilla or any framework)
- No comment system libraries — build all threading and voting logic yourself

## Scoring Criteria
- **Functional (40%)**: Comments, replies, and voting work correctly; threading displays properly
- **Quality (20%)**: Clean code, handles edge cases (deep nesting, deleted parents), no crashes
- **Fidelity (25%)**: All features implemented including markdown, permalinks, collapse/expand, report
- **Speed (15%)**: Time bonus