[css-grid-3] Make align-self/justify-self align including adjacent extra space about csswg-drafts HOT 8 OPEN

By "flex behavior" you mean "treat %s as indefinite if they're resolving against an indefinite dimension" (and stretching doesn't make a dimension become definite).

from csswg-drafts.

Oh yeah, that makes sense. You need it to work like this, in fact - you can't align the contents of the column as a whole, because spanning items cross columns. So it needs to align each contiguous run of single-column items.

Does this then imply that spanning items can never be aligned in that axis? We don't otherwise meaningfully distinguish between a masonry of single-column items and an identical masonry with double the half-width columns and all items being two-column spanners, but I don't think I'm opposed to making that distinction.

from csswg-drafts.

Generally supportive of the stretch capability.

Two points:

• When defining stretch needs to be explicit on how percentages resolve. E.g. potentially want flex behaviour here.
• Need to be careful for the other non-stretch values, e.g. it runs into the same "ordering becomes unclear" issue, but perhaps less so here.

from csswg-drafts.

Oh, I didn't properly read the title - I don't think this is appropriate for *-self to do, for the same reason we don't let align-self work in Block Layout. I think this should be a *-content behavior.

from csswg-drafts.