4.5 introduces some changes to CSS, so I wanted to provide an overview of those and how they might affect you.   IE11 Firstly, we've completely dropped support for IE11. This means you'll start to see newer CSS methods being used that IE11 does not support.    Atomic classnames One thing you'll notice as you read on is we're moving towards using atomic classnames for utility styles. What does that mean? Basically, each classname is just a convenience helper for appl