diff --git a/css-grid-1/Overview.bs b/css-grid-1/Overview.bs
index 9ad93f19e805..8df619a76874 100644
--- a/css-grid-1/Overview.bs
+++ b/css-grid-1/Overview.bs
@@ -4634,7 +4634,7 @@ Fragmenting Grid Layout
Grid containers can break across pages
between rows or columns
- and inside items.
+ as well as within rows and inside items.
The break-* properties apply to grid containers
as normal for the formatting context in which they participate.
This section defines how they apply to grid items
@@ -4644,7 +4644,7 @@ Fragmenting Grid Layout
The following breaking rules refer to the fragmentation container as the “page”.
The same rules apply in any other fragmentation context.
(Substitute “page” with the appropriate fragmentation container type as needed.)
- See the CSS Fragmentation Module [[!CSS3-BREAK]].
+ See the CSS Fragmentation Module [[!CSS-BREAK-3]].
The exact layout of a fragmented grid container is not defined in this level of Grid Layout.
@@ -4659,15 +4659,32 @@ Fragmenting Grid Layout
are propagated to the grid container.
- A forced break inside a grid item effectively increases the size of its contents;
- it does not trigger a forced break inside sibling items.
-
-
- Class A break opportunities occur
+ Class A break opportunities occur
between rows or columns (whichever is in the appropriate axis),
- and Class C break opportunities occur
+ and Class C break opportunities occur
between the first/last row (column) and the grid container's content edges.
- [[!CSS3-BREAK]]
+ [[!CSS-BREAK-3]]
+
+
+ A grid track may be fragmented
+ by fragmenting all items in the track at that point
+ in accordance with their own fragmentation constraints
+ (including consideration of 'break-inside' on the items themselves).
+ Fragmentation breaks within a grid item
+ effectively increase the size of its content,
+ and can thereby increase the effective size of the track
+ (and consequently the size of other items in the track).
+
+ It is undefined to what extent such changes in the size of the track
+ impact the sizes of other tracks and/or the grid container itself;
+ however the UA should avoid causing overflow.
+
+ A forced break inside a grid item affects only that item;
+ it does not trigger a parallel forced break
+ inside the contents of sibling items.
+ But it can cause fragmentation of sibling items
+ by stretching them across the break
+ through its impact on the size of its row(s).
When a grid container is continued after a break,
@@ -4788,6 +4805,15 @@ Changes
This section documents the changes since previous publications.
+
+
+
+ -
+ Clarified how tracks and items within tracks fragment.
+ (Issue 13870)
+
+
diff --git a/css-grid-2/Overview.bs b/css-grid-2/Overview.bs
index 7882bcfea94b..30c4533b721a 100644
--- a/css-grid-2/Overview.bs
+++ b/css-grid-2/Overview.bs
@@ -5327,7 +5327,7 @@ Fragmenting Grid Layout
Grid containers can break across pages
between rows or columns
- and inside items.
+ as well as within rows and inside items.
The break-* properties apply to grid containers
as normal for the formatting context in which they participate.
This section defines how they apply to grid items
@@ -5337,7 +5337,7 @@ Fragmenting Grid Layout
The following breaking rules refer to the fragmentation container as the “page”.
The same rules apply in any other fragmentation context.
(Substitute “page” with the appropriate fragmentation container type as needed.)
- See the CSS Fragmentation Module [[!CSS3-BREAK]].
+ See the CSS Fragmentation Module [[!CSS-BREAK-3]].
The exact layout of a fragmented grid container is not defined in this level of Grid Layout.
@@ -5352,15 +5352,32 @@ Fragmenting Grid Layout
are propagated to the grid container.
- A forced break inside a grid item effectively increases the size of its contents;
- it does not trigger a forced break inside sibling items.
-
-
- Class A break opportunities occur
+ Class A break opportunities occur
between rows or columns (whichever is in the appropriate axis),
- and Class C break opportunities occur
+ and Class C break opportunities occur
between the first/last row (column) and the grid container's content edges.
- [[!CSS3-BREAK]]
+ [[!CSS-BREAK-3]]
+
+
+ A grid track may be fragmented
+ by fragmenting all items in the track at that point
+ in accordance with their own fragmentation constraints
+ (including consideration of 'break-inside' on the items themselves).
+ Fragmentation breaks within a grid item
+ effectively increase the size of its content,
+ and can thereby increase the effective size of the track
+ (and consequently the size of other items in the track).
+
+ It is undefined to what extent such changes in the size of the track
+ impact the sizes of other tracks and/or the grid container itself;
+ however the UA should avoid causing overflow.
+
+ A forced break inside a grid item affects only that item;
+ it does not trigger a parallel forced break
+ inside the contents of sibling items.
+ But it can cause fragmentation of sibling items
+ by stretching them across the break
+ through its impact on the size of its row(s).
When a grid container is continued after a break,
@@ -5438,6 +5455,15 @@ Security Considerations {#security}
Changes
+
+
+
+ -
+ Clarified how tracks and items within tracks fragment.
+ (Issue 13870)
+
+