A minimal library which polyfills the ResizeObserver API and is entirely based on the latest Draft Specification.

Recommended by: CSS-Tricks

Simple quantity queries mixins for Sass. Use quantity as a condition to style your items.

You may want to read the original Flexbox Holy Albatross post but basically, I missed a step (I was hungover): You can switch between horizontal (multi-column) to vertical (single column) Flexbox layouts just using flex-basis. No min-width or max-width needed — in fact, they just restrict Flexbox from doing its beautiful Flexbox thing.