PriyaSingh0201/AI-Symptom-Checker-phase-1-4 ? reverse-engineered prompt

Build me a full stack Flask web app for an AI symptom checker that feels like a polished healthcare product, not a generic chat bot.

I want users to sign up, log in, and save their symptom assessments. The main flow should let someone enter symptoms and a bit of patient info, then get back an explainable result with the top possible conditions, confidence scores, severity, what kind of doctor to see, and simple home care advice when it is safe. If the symptoms sound urgent, show a clear emergency warning and skip the normal advice.

Please also include an AI chat assistant that remembers the current consultation, a follow up question flow that helps refine the result, a history page with past assessments, a downloadable PDF report, voice input for symptoms, dark mode, and English and Hindi switching. If an external AI key is not available, make sure it still works with a built in rule based fallback.

Use a clean modern design, make it responsive, and keep the code organized so it is easy to run locally and deploy later.