Код-ревью: экран ленты

Widget build(BuildContext context) {
  final width = MediaQuery.of(context).size.width;
  return SingleChildScrollView(
    child: Column(children: [
      Container(height: 200, width: width, child: const Header()),
      GridView.count(
        crossAxisCount: width > 600 ? 4 : 2,
        shrinkWrap: true,
        children: categories.map((c) => CategoryTile(c)).toList(),
      ),
      ListView(
        shrinkWrap: true,
        children: posts.map((p) => PostCard(p)).toList(),
      ),
    ]),
  );
}