Currently, probably not. I'm using ant design right now and it uses Flexbox as its underlying layout engine. I think Bootstrap 4 is the same. Once they ditch

Currently, probably not. I'm using ant design right now and it uses Flexbox as its underlying layout engine. I think Bootstrap 4 is the same. Once they ditch support for IE11, then they'll probably move to CSS Grid, but at that point you really don't need a UI toolkit to be based on CSS Grid. You either just use the css directly, or have a UI toolkit-independent component wrappers around the grid.