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

    # Security headers
    add_header X-Frame-Options "SAMEORIGIN" 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 compression
    gzip on;
    gzip_vary on;
    gzip_min_length 1024;
    gzip_proxied any;
    gzip_comp_level 6;
    gzip_types
        text/plain
        text/css
        text/xml
        text/javascript
        application/json
        application/javascript
        application/xml+rss
        application/atom+xml
        image/svg+xml;

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

    # Main site
    location / {
        try_files $uri $uri/ /index.html;
    }

    # Assets directory for downloads
    location /assets/ {
        add_header Content-Disposition "attachment";
        add_header Content-Type "application/octet-stream";
    }

    # Health check endpoint
    location /health {
        access_log off;
        return 200 "healthy\n";
        add_header Content-Type text/plain;
    }

    # Block access to sensitive files
    location ~ /\. {
        deny all;
    }

    location ~ ~$ {
        deny all;
    }
}