> https://drafts.csswg.org/css-text-4/#text-group-align-property Group alignment is performed by finding the line box with the shortest remaining space and adding that amount of space as padding to one or both sides of the line box, reducing the amount of space available for its contents; text alignment is then applied to its contents within the remaining space. All descendant in-flow line boxes within the same block formatting context are considered both when searching for the shortest remaining space and when adding the padding; the contents of descendants that establish independent formatting contexts are skipped.
<rdar://problem/103663524>
Pull request: https://github.com/WebKit/WebKit/pull/8052
Pull request: https://github.com/WebKit/WebKit/pull/8262