Controlling macro and micro layout in a new era of responsive web design.
Responsive Design Today
Today, when using the term: "responsive design", you are most likely thinking about using media queries to change layout when resizing a design from mobile size, to tablet size, through to desktop size.
But soon, this perception of responsive design may be considered as outdated as using tables for page layout.
Viewport-based media queries give you some powerful tools, but lack a lot of finesse. They lack the ability to respond to user needs, and the ability to inject responsive styles into components themselves.
You can use global viewport information to style your components, but they still don't own their styles, and that doesn't work when our design systems are component-based and not page-based.
The good news is, the ecosystem is changing, and it's changing pretty rapidly. CSS is evolving, and a new era of responsive design is right on the horizon.
We see this happen about every 10 years. 10 years ago, around 2010-2012, we saw a huge change with mobile and responsive design, and the emergence of CSS3.