AFAIK every browser but IE11 supports the modern basic grid syntax. Edge has supported the new syntax since Edge 16 which is old enough to be widely deployed in

AFAIK every browser but IE11 supports the modern basic grid syntax. Edge has supported the new syntax since Edge 16 which is old enough to be widely deployed in enterprise now. So as far as I'm concerned that's the "Vast majority of browsers" and for static grids I just use the old syntax as a fallback for IE11 https://caniuse.com/#feat=css-grid https://caniuse.com/#feat=css-grid