The code for lib/widgets/crossword_info_widget.dart

is missing the required imports (in the web page that describes what to do) and does not compile - however having copy / pasted the name of the file and checked the source I see that the source is OK, so it's a display issue of some sort for the web page).

I added these imports locally to make it work:

import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

import '../providers.dart';
import '../utils.dart';
import './ticker_builder.dart';