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

    # SPA history fallback: unknown paths serve the app shell so client-side
    # routing works on hard reloads and deep links.
    location / {
        try_files $uri $uri/ /index.html;
    }

    # Never cache the shell or the runtime config, so a redeploy or an env
    # change is picked up on the next load. The hashed assets they point to are
    # cached immutably below.
    location = /index.html { add_header Cache-Control "no-store"; }
    location = /config.js  { add_header Cache-Control "no-store"; }

    location /assets/ {
        add_header Cache-Control "public, max-age=31536000, immutable";
    }
}