> You now can't use that header anywhere else, meaning the it's non-composable. You end up writing less, and more maintainable CSS when you treat components as

> You now can't use that header anywhere else, meaning the it's non-composable. You end up writing less, and more maintainable CSS when you treat components as immutable and composable. You can use that header on any page and you're not going to re-use it on the same page. Why does it need to be "compose-able" at all? Either way this is a silly argument because there is no problem here. You have a set of CSS styles you want applied to an element on the page that will never have a copy, etc? You can use ID or Class and you can even swap them with the same level of difficulty. This is entirely a non-issue no matter what way you go; it's more of a style thing.