mia, Blink & Webkit both have beta support for #CSS
align-content
on block layouts (no grid/flex required):https://codepen.io/miriamsuzanne/pen/VwNYxLV?editors=1100
Blink also has self-alignment/justification of absolutely positioned elements:
https://codepen.io/miriamsuzanne/pen/gOybzmO?editors=1100
(see Chrome/etc 123 & Safari TP 17.4)