Building a responsive image

https://medium.com/9elements/building-a-responsive-image-e4c6229fa1f6
Tour-de-force on SVG and media queries. 

How to make responsiveness super simple with CSS Variables

https://medium.freecodecamp.org/how-to-make-responsiveness-super-simple-with-css-variables-8c90ebf80d7f
CSS variables and grid layout combine to make responsive grids much easier.

The 100% correct way to do CSS breakpoints

https://medium.freecodecamp.com/the-100-correct-way-to-do-css-breakpoints-88d6a5ba1862#.gq7zx1ayl
A wonderful, common-sense approach to setting CSS breakpoints.

Viewport Unit Based Typography

http://zellwk.com/blog/viewport-based-typography/

nicely-done #tutorial on #viewport-based #typography.