diff --git a/css-env-1/Overview.bs b/css-env-1/Overview.bs
index 3235dffe8e07..705f0d111768 100644
--- a/css-env-1/Overview.bs
+++ b/css-env-1/Overview.bs
@@ -126,6 +126,42 @@ safe area rectangle.
+Safe area maximum inset variables {#safe-area-max-insets}
+------------------------------------------------------------------
+
+
+
+ Name
+ | Value
+ | Number of dimensions
+ |
+ safe-area-max-inset-top
+ | <>
+ 0 (scalar)
+ |
+ safe-area-max-inset-right
+ | <>
+ 0 (scalar)
+ |
+ safe-area-max-inset-bottom
+ | <>
+ 0 (scalar)
+ |
+ safe-area-max-inset-left
+ | <>
+ 0 (scalar)
+ | | | | |
+
+The safe area maximum insets are four [=environment variables=]
+that are tied to the safe area inset variables.
+Unlike the safe area inset variables which are dynamic values,
+the safe area maximum insets are static values
+that represent the maximum value of their dynamic counterpart
+when dynamic UA interfaces are retracted,
+making the [=layout viewport=] size the [=large viewport size=].
+
+
+
Viewport segment variables {#viewport-segments}
------------------------------------------------------------------