This can be a browser specified issue where it cannot understand ES6 terms. Because sometimes browsers complain the import keyword even though it is part of JS. And to overcome that you need to tell the browser you are using modules by declaring type=“module” inside script tag in index.html.
Probably this is the same issue, probably not.
PS - Google searching the error gives me results related to a same issue like above but for TypeScript. May be FCC is using TS?