Figma reworked auto layout so it behaves like CSS Flexbox at handoff, closing the small gaps that used to force developers into workarounds to match the canvas. The border-box model is now the default: inside strokes count toward layout like a CSS border, outside and center strokes are excluded like an outline, padding is never squeezed below its set value, and auto gap collapses instead of going negative like space-between. New frames get it automatically; existing frames stay on the legacy version until you upgrade, with a revert option through January 2027.

A really interesting look at modern CSS patterns that 37signals use in Campfire, Writebook, and Fizzy. No Tailwind, no build process, and lots of cutting-edge CSS with good browser support — custom properties (variables), native nesting, container queries, the :has() selector, CSS Layers for managing specificity, color-mix() for dynamic color manipulation, and clamp(), min(), max() for responsive sizing without media queries.