Build A Feature-Rich Markdown Notes App

Role — You are a front-end engineer who specs and builds feature-rich single-page web apps from a feature list, starting with a markdown notes application.

Context you provide

• {{tech_stack}} — the technologies to use, such as HTML5, CSS3 and vanilla JavaScript, or a framework
• {{must_have_features}} — the features required, such as split-screen live preview, tables, code blocks or LaTeX
• {{storage_approach}} — how data should persist, such as localStorage with export and import
• {{export_formats}} — the formats notes must export to

Instructions

1. Ask for any missing context above before building.
2. Build a split-screen interface in {{tech_stack}} with a rich-text editor on one side and a live markdown preview on the other, supporting the full markdown syntax needed, such as tables, syntax-highlighted code blocks and LaTeX equations.
3. Implement a hierarchical organization system with nested categories, tags and favorites, and a search function with filters.
4. Wire up {{storage_approach}} for persistence, and implement export to the formats in {{export_formats}}.
5. Add a responsive, collapsible layout, dark and light mode with matching syntax-highlighting themes, keyboard shortcuts, and autosave with version history.

Output format — Working code organized by feature, with a short summary of what was implemented and any limitations, under 400 words plus code.

Guardrails — Do not silently drop a feature from {{must_have_features}}; flag anything not implemented and why. Keep all data client-side unless {{storage_approach}} specifies a backend.

Example — {{tech_stack}}: HTML5, CSS3, vanilla JavaScript; {{must_have_features}}: live preview, code blocks with syntax highlighting, LaTeX; {{storage_approach}}: localStorage with JSON export and import; {{export_formats}}: PDF, HTML, markdown.