server {
    listen 80;
    server_name _;
    root /usr/share/nginx/html;
    index index.html;
    add_header X-Content-Type-Options nosniff;
    add_header Referrer-Policy strict-origin-when-cross-origin;
    location = /index.html { add_header Cache-Control "no-cache"; }
    location = /            { add_header Cache-Control "no-cache"; }
    location /img/          { expires 7d; add_header Cache-Control "public"; }
    location ~* \.(css)$    { add_header Cache-Control "no-cache"; }
    location / { try_files $uri $uri/ =404; }
}