Design a clean, modern React and Shadcn webpage using TailwindCSS 3 for a simple free audio converter. The tool lets users upload audio/video files (e.g., WAV, MP3, MP4, AAC, FLAC, OGG) and converts them using ffmpeg. The interface should feel friendly and non-technical, with very few options. Focus on a smooth user flow:
- Large drag-and-drop upload area
- Auto-detect input format and a minimal dropdown for output format
- Clear convert button and progress indicator
- Simple success state with a download button
- Desktop-first layout, but responsive for mobile
- Download Section appears after conversion. Big "Download" button with file info
- Footer. Brief "Powered by FFmpeg" note. Add a disclaimer that files are not sent to any servers. All the data is processed in the user's browser.
- Light, welcoming visual style with good spacing and intuitive icons
No advanced settings, no intimidating terminology — just a clean, polished, accessible experience. Incorporate visual elements and layout structures that highlight the core functionality—file upload, format selection, and conversion initiation—while ensuring a visually appealing and accessible user experience.