server {

  listen 80;

  location ^~ /admin {
    alias /etc/nginx/html;
    try_files $uri $uri/index.html @admin;
  }

  location @admin {
    rewrite ^.*$ /admin/index.html last;
  }

  error_page   500 502 503 504  /50x.html;

  location = /50x.html {
    root   /usr/share/nginx/html;
  }
}