These look like some interesting css options, though I'll comment that adding grid placement options is less new, and more just minor syntactic sugar. Plus, basic grid layout styling being added to css will rarely do what we actually want them to do.

Accounting for scrollbar appearance and auto-updtating the width of the frame/window is pretty useful, though. Not having the horizontal scroll bar suddenly appear when a vertical bar is needed due to dynamic elements is highly preferable.