I wouldn’t use CSS in early Internet Explorer as a good example. There were quite a few cases where they shipped something prematurely based off an early draft, then the final spec. changed, making Internet Explorer incompatible with the standards and other browsers. That’s how the box model ended up the way that it did, for example. The draft was originally border-box behaviour, Internet Explorer implemented it too soon, then the specification changed to content-box behaviour and all the other browsers implemented it.