Build an intuitive, professional, and highly responsive web ...

Prompt

Build an intuitive, professional, and highly responsive web application designed for visualizing, playing, and sharing custom chord progressions. The user interface should feature a built-in interactive piano that visually highlights keys during playback and supports direct input alongside a flexible text parser capable of interpreting standard chord names, symbols, and harmonic notation. To deliver smooth audio transitions, incorporate an algorithmic voice-leading engine that dynamically calculates the most natural chord voicings given the active key signature and upcoming harmonic movement. Provide comprehensive export capabilities, allowing users to save their progressions as standard MIDI files for use in external audio software or generate clean, professionally formatted chord sheets in PDF format for printing and sharing. System state and user progress must be continuously auto-saved to the browser's local storage to prevent data loss. Furthermore, enable custom project file management by implementing export and import capabilities for a structured JSON payload using a custom file extension (.prog), allowing users to seamlessly save, share, and reload their work.

A system prompt was added to support web rendering