Re: [csswg-drafts] [css-gaps-1] `overlap-join` with `between` rule visibility (#13697)

@kbabbitt  @oSamDavis @jav099 @alisonmaher and I chatted some more today and mostly aligned that a variant of Option 3 was our best bet. Namely, we don't think that we will need to later add edge|interior support, as we have no known use cases that wouldn't be satisfied instead by intersecting|dangling.  If we did end up needing to expand to support edge|interior distinction, we would need to do so with a function similar to option 2a, to avoid the problems of turning a shorthand into a longhand.

So to recap the proposal, the set of 8 longhand properties would look like:
```
[column|row]-rule-[intersecting|dangling]-inset-[start|end]: <length-percentage> | overlap-join
```

Any existing references from edge|interior would be updated to intersecting|dangling, so the `rule-inset` shorthand would be:
```
rule-inset: dangling-start dangling-end? [/ intersecting-start intersecting-end?]?
```

`overlap-join` would assign `0px` as the corresponding `dangling` value and `calc( -(50% + crossing_decoration_width/2) )` for the `intersecting` value. This means you could specify just the keyword to get the expected common join case:

```
rule-inset: overlap-join;
```

or you could make a modification of just the dangling portion from `0px` to `3px` by doing something as simple as:
```
rule-inset: 3px / overlap-join;
```

*If* we ever had to add support for distinguishing between interior and exterior/edge in the future (which we are betting we will not have to do), we could do so with a `exterior-interior(<inset-value>, <inset-value>)` function.

Assuming there is broader agreement on all of that, the remaining piece is bikeshedding the names. The group seemed to like `intersecting`, but there were mixed opinions on what the other name should be. Some options include:

* intersecting/nonintersecting
* intersecting/hanging
* intersecting/trailing
* intersecting/spoked
* intersecting/bounds
* intersecting/discontinuous
* intersecting/jagged
* intersecting/splintered
* intersecting/severed
* intersecting/edge
* open/closed
* blocked/unblocked

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Received on Tuesday, 7 April 2026 23:49:39 UTC