This PR resolves persistent Vercel deployment failures by addressing multiple configuration and build issues that were causing the same deployment errors repeatedly.

Issues Fixed

1. CSS PostCSS Build Errors

The build was failing with PostCSS errors due to incorrect @import statement placement:

[vite:css][postcss] @import must precede all other statements (besides @charset or empty @layer)

Root Cause: CSS @import statements were placed after CSS rules in src/styles/viral-brand.css, violating CSS specification.

Fix: Moved all @import statements to the top of the file, before any CSS rules or variable declarations.

2. CORS Configuration Issues

The API was rejecting requests from deployed frontend due to hardcoded localhost origins:

// Before: Only localhost allowed
origin: ['http://localhost:5173', 'http://localhost:3000']

// After: Dynamic production domain support
origin: function (origin, callback) {
  // Allow any vercel.app domain in production
  if (process.env.NODE_ENV === 'production' && origin.includes('.vercel.app')) {
    return callback(null, true)
  }
  // ... additional logic
}

3. Vercel Configuration Improvements

Updated both frontend and API vercel.json files with proper build settings:

• Added explicit buildCommand and installCommand for frontend
• Added framework detection for better optimization
• Set function timeout limits for API endpoints
• Added NODE_ENV=production for proper environment detection

4. Environment Variable Validation

Added runtime validation for required environment variables in the API server:

const requiredEnvVars = {
  'VITE_SUPABASE_URL': process.env.VITE_SUPABASE_URL,
  'SUPABASE_SERVICE_ROLE_KEY': process.env.SUPABASE_SERVICE_ROLE_KEY,
  'OPENAI_API_KEY': process.env.OPENAI_API_KEY
}

This provides clear error messages when environment variables are missing or contain placeholder values.

Documentation

Created comprehensive VERCEL_DEPLOYMENT_FIX.md guide with:

• Step-by-step deployment instructions
• Complete list of required environment variables
• Troubleshooting guide for common issues
• Verification steps to confirm successful deployment

Updated main README to reference the deployment fix guide.

Testing

• ✅ Frontend builds cleanly without CSS warnings
• ✅ API server validates syntax correctly
• ✅ CORS configuration tested with multiple domain patterns
• ✅ Environment variable validation working as expected

These changes should resolve the persistent "SAME error" deployment issues on Vercel by addressing the root causes rather than symptoms.

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