server {

    root /usr/share/nginx/html;
    listen 80;

    access_log off;

    charset UTF-8;

    set_real_ip_from 172.16.0.0/12;
    set_real_ip_from 10.0.0.0/8;

    add_header X-Frame-Options "DENY";
    add_header Referrer-Policy "no-referrer";
    add_header Access-Control-Allow-Origin "*";
    add_header Content-Security-Policy "default-src 'none'; script-src 'self'; img-src data: 'self'; style-src 'self' 'unsafe-inline'; font-src data: 'self'; object-src data:; base-uri 'none'; form-action 'none'; worker-src 'self'; connect-src 'self'; manifest-src 'self'";
    add_header Feature-Policy "geolocation 'none'; midi 'none'; notifications 'none'; push 'none'; sync-xhr 'none'; microphone 'none'; camera 'none'; magnetometer 'none'; gyroscope 'none'; speaker 'none'; vibrate 'none'; fullscreen 'self'; payment 'none'; usb 'none';";
    add_header Allow "GET, HEAD" always;

    if ( $request_method !~ ^(GET|HEAD)$ ) {
      return 405;
    }

    location / {
      root   /usr/share/nginx/html;
      index  index.json;
      try_files  $uri $uri/index.json $uri.html =404;
    }

    error_page  404              /404.html;

    # redirect server error pages to the static page /50x.html
    #
    error_page   500 502 503 504  /50x.html;
    location = /50x.html {
        root   /usr/share/nginx/html;
    }
}