server {
  listen 80;
  server_name _;
  root /usr/share/nginx/html;
  include /etc/nginx/mime.types;

  # Serve hashed assets aggressively; keep index/service worker cacheable but not immutable.
  location /assets/ {
    try_files $uri =404;
    expires 30d;
    add_header Cache-Control "public, max-age=2592000, immutable";
  }

  location /icons/ {
    try_files $uri =404;
    expires 30d;
    add_header Cache-Control "public, max-age=2592000";
  }

  location = /flutter_service_worker.js {
    add_header Cache-Control "no-cache";
    try_files $uri =404;
  }

  location / {
    try_files $uri $uri/ /index.html;
  }
}