server {
    listen 80;
    server_name _;

    root /usr/share/nginx/html;
    index index.html;

    # Health check endpoint (no logging)
    location = /health.txt {
        access_log off;
        return 200 "ok\n";
        add_header Content-Type text/plain;
    }

    # React Router — all non-asset paths serve index.html
    location / {
        try_files $uri $uri/ /index.html;
    }

    # Static assets — aggressive caching (Vite hashes filenames)
    location ~* \.(js|css|woff2?|ttf|eot|svg|png|jpg|jpeg|gif|ico|wasm)$ {
        expires 1y;
        add_header Cache-Control "public, immutable";
        access_log off;
    }

    # Security headers
    add_header X-Frame-Options "DENY" always;
    add_header X-Content-Type-Options "nosniff" always;
    add_header Referrer-Policy "strict-origin-when-cross-origin" always;
    add_header Content-Security-Policy "default-src 'self'; script-src 'self' 'unsafe-inline'; style-src 'self' 'unsafe-inline' https://fonts.googleapis.com; font-src 'self' https://fonts.gstatic.com; img-src 'self' data: blob:; connect-src 'self' wss:;" always;

    # Gzip
    gzip on;
    gzip_types text/plain text/css application/json application/javascript text/xml application/xml application/xml+rss text/javascript application/wasm;
    gzip_min_length 1000;
}