Really great work by the Mozilla gang. Curious, as they already have MDN for CSS Grid, which isn’t only a straight reference, they have plenty of “guides”. Not that I’m complaining, the design and learning flow of this are fantastic. And of course, I’m a fan of the “View on CodePen” links ;)
There are always lots of ways to learn something. I’m a huge fan of Rachel Andrew’s totally free video series and our own guide. This also seems a bit more playground-like.