WordCamp Europe 2020
Subgrid is already available in Firefox since version 71 (released Dec 2019).
Subgrid is currently only available in Firefox. Not in Chrome, Safari, Edge, etc.
subgrid is a new value for two properties:
Line numbers in a subgrid start from 1 again - they do not use the line numbers of the parent grid.
If gutters are defined on the parent grid container, it will be passed to the subgrid
Properties: gap, column-gap and row-gap