[csswg-drafts] [css-lists] Add `counter-increment: <counter-name> step(<integer>)` that negates integer in reversed lists (#6800)

Loirooriol has just created a new issue for https://github.com/w3c/csswg-drafts:

== [css-lists] Add `counter-increment: <counter-name> step(<integer>)` that negates integer in reversed lists ==
Most of the behavior of HTML lists numbering can now be explained in CSS terms, but there is still this remaining piece of magic:
https://drafts.csswg.org/css-lists/#list-item-counter

> unless the `counter-increment` property explicitly specifies a different increment for the `list-item` counter, it must be incremented by 1 on every list item, or if the counter is reversed, it must be incremented by -1 on every list item instead

When using their own custom counters, authors have no way to specify an amount in `counter-increment`, and increase by that amount in normal lists, or decrease in reversed lists.

As @MatsPalmgren proposed in https://github.com/w3c/csswg-drafts/issues/6231#issuecomment-945718767, we could allow `counter-increment` to accept a `step(<integer>)` that would just do that.

Then, the implicit `list-item` counter would get `counter-increment: list-item step(1)` on list items, that would behave as described in the quote above.

This feature would also make `counter-reset: reversed(<counter-name>) <integer>` useful, since without `step()` it behaves exactly as `counter-reset: <counter-name> <integer>` for counters other than `list-item` when the integer is not omitted (#6231).

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/6800 using your GitHub account


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Received on Friday, 5 November 2021 15:47:29 UTC