[css-align-3][css-overflow-3] Content alignment on scroll containers extends scrollable area #4957

[fantasai]

See #4957.

Review questions:

• Should we collapse the concepts of "scroll origin position" and "initial scroll position" now that they coincide even in the presence of alignment? If so, which word should we use?
• I think we can close the two issues marked in https://drafts.csswg.org/css-overflow-3/#scrolling ?
• Having the "The scrollable overflow area is the union of:" list before the definition of key terms like “scroll position” seems wrong. Should I pull it out into its own subsection? Where?

[tabatkins]

Should we collapse the concepts of "scroll origin position" and "initial scroll position" now that they coincide even in the presence of alignment? If so, which word should we use?

Yes, we should collapse. For the term, I forget whether we're actually adjust the scroll origin (so 0 is at the end, or whatever) or if we're just starting it out at a non-zero value. Which is the case, we should lean toward that term imo.

I think we can close the two issues

Is the baseline one answered? I don't see anything in the edits apparently addressing that, but maybe it falls out of them in a more general way.

Having the "The scrollable overflow area is the union of:" list before the definition of key terms like “scroll position” seems wrong. Should I pull it out into its own subsection? Where?

Can you just swap the sections? It's already practically the entire subsection anyway, I don't think dropping it into a further subsection would really help.

[fantasai]

Rebased.

Given the addition of scroll-initial-target, I think we need to distinguish the [=scroll origin position=] and the [=initial scroll position=].

[fantasai]

Split out the ordering question into #11895

I'm going to merge this now.