server {
    listen 80;
    server_name _;  # Replace with your domain

    # Frontend static files
    location / {
        root /opt/fluentgerman/frontend;
        try_files $uri $uri/ /index.html;
    }

    # API proxy
    location /api/ {
        proxy_pass http://127.0.0.1:8000;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;

        # SSE support (for chat streaming)
        proxy_buffering off;
        proxy_cache off;
        proxy_read_timeout 300s;
    }

    # Security headers
    add_header X-Frame-Options DENY always;
    add_header X-Content-Type-Options nosniff always;
    add_header X-XSS-Protection "1; mode=block" always;
    add_header Referrer-Policy strict-origin-when-cross-origin always;

    # Gzip
    gzip on;
    gzip_types text/plain text/css application/json application/javascript;
    gzip_min_length 256;

    # Upload size (for voice audio)
    client_max_body_size 25M;
}