Subgrid will be available in Firefox 71 (Dec 3), and you can use it already in Firefox Nightly – but there’s no need to wait. Subgrid works great as a quick enhancement on top of you existing layouts!
It’s a common pattern to align form labels and inputs in grid-like layout. I’ll show you how to do it quickly using CSS subgrid, with several quick fallbacks.
Laying out Forms using Subgrid
and fallbacks for legacy browsers
Repost from Mozilla Developer