server {
    listen 80;
    server_name localhost;
    root /usr/share/nginx/html;
    index index.html index.htm;

    # Handle React Router (client-side routing)
    location / {
        try_files $uri $uri/ /index.html;
    }

    # Security headers
    add_header X-Frame-Options "SAMEORIGIN" always;
    add_header X-XSS-Protection "1; mode=block" always;
    add_header X-Content-Type-Options "nosniff" always;
    add_header Referrer-Policy "no-referrer-when-downgrade" always;

    # Cache static assets
    location ~* \.(js|css|png|jpg|jpeg|gif|ico|svg)$ {
        expires 1y;
        add_header Cache-Control "public, immutable";
    }

    # Gzip compression
    gzip on;
    gzip_vary on;
    gzip_min_length 1024;
    gzip_comp_level 6;
    gzip_types
        application/javascript
        application/json
        text/css
        text/javascript
        text/plain
        text/xml;
}