Subgrids thinking out loud
A great post from Igalia focussing on a one aspect of the Grid Layout, the subgrid. Igalia have been working on the Chrome/Blink and Safari/WebKit Grid Layout implementation so know a thing or two about this.
Subgrids feature allows us to create nested grids that share lines with the grid container.
An excerpt from Subgrids thinking out loud
We just define the size of the tracks on the main grid container, and the subgrid use those sizes to layout its items.