diff --git a/css-overflow-5/Overview.bs b/css-overflow-5/Overview.bs
index e03c7b34a8e..f508c79720e 100644
--- a/css-overflow-5/Overview.bs
+++ b/css-overflow-5/Overview.bs
@@ -406,7 +406,7 @@ Selecting The Active Scroll Marker: the '':target-current'' pseudo-class
Note: If the user tabs away the focus behavior will ensure they tab into the relevant content.
-
+
When a [=scroll marker=] is activated,
the next tabindex-ordered focus navigation will focus the [=scroll target=] if it is focusable,
@@ -517,10 +517,34 @@ Or the non-native rendering, aka ''appearance:none''?
If the former, we'll obviously need to define the interaction with 'appearance'.
-
-Focus Navigation Order
+
+Focus behavior
The above features generate several focusable pseudo-elements.
+This section defines some of the focus related behaviors.
+
+
+The active element
+
+When a ''::scroll-button()'' or ''::scroll-marker'' is focused,
+the {{DocumentOrShadowRoot/activeElement}}
+is the [=scroll container=] the control is associated with.
+
+
+Focus related pseudo-classes
+
+When a ''::scroll-button()'' or ''::scroll-marker'' is focused,
+none of the focus related pseudo-classes '':focus'', '':focus-visible'' and '':active'' match on the [=scrolling container=].
+Instead, '':focus'' and, when relevant '':focus-visible'', match on the focused pseudo-element.
+'':active'' matches on the pseudo-element while it is being activated.
+'':focus-within'' matches on the [=scroll container=] and all of its ancestors in the [=flat tree=].
+
+When a ''::scroll-marker'' is focused,
+'':focus-within'' additionally matches on the ''::scroll-marker-group'' it belongs to.
+
+
+Focus navigation order
+
While these pseudo-elements have a defined position in the element tree,
this isn't an optimal position for focus navigation
(aka "tab order")