From ca7ee9ed4cf0d0f9b91fcf3a05e8b21550ed732e Mon Sep 17 00:00:00 2001
From: Ravi <7014230+arelra@users.noreply.github.com>
Date: Fri, 12 Jun 2026 08:49:32 +0100
Subject: [PATCH] Fix interscroller stacking context

Following grid update to standard layout
https://github.com/guardian/dotcom-rendering/pull/15428
---
 dotcom-rendering/src/lib/adStyles.ts  | 2 ++
 dotcom-rendering/src/lib/getZIndex.ts | 3 +++
 2 files changed, 5 insertions(+)

diff --git a/dotcom-rendering/src/lib/adStyles.ts b/dotcom-rendering/src/lib/adStyles.ts
index 9d87c6e5a7a..87d4df26645 100644
--- a/dotcom-rendering/src/lib/adStyles.ts
+++ b/dotcom-rendering/src/lib/adStyles.ts
@@ -2,6 +2,7 @@ import { css } from '@emotion/react';
 import { adSizes, constants } from '@guardian/commercial-core';
 import { from, textSans12, until } from '@guardian/source/foundations';
 import { palette } from '../palette';
+import { getZIndex } from './getZIndex';
 
 const labelHeight = constants.AD_LABEL_HEIGHT;
 
@@ -137,6 +138,7 @@ const spacefinderAdSlotContainerStyles = css`
 			/* this fixes inter-scrollers stealing mouse events */
 			overflow: hidden;
 			position: relative;
+			z-index: ${getZIndex('interscrollerAd')};
 
 			/* position the iframe absolutely (relative to the slot) so that it is in the correct position to detect viewability */
 			.ad-slot__content {
diff --git a/dotcom-rendering/src/lib/getZIndex.ts b/dotcom-rendering/src/lib/getZIndex.ts
index 946e25c784e..37750dcdf2b 100644
--- a/dotcom-rendering/src/lib/getZIndex.ts
+++ b/dotcom-rendering/src/lib/getZIndex.ts
@@ -57,6 +57,9 @@ const indices = [
 	// Edition selector in nav - needs to be below stickyAdWrapper
 	'editionDropdown',
 
+	// Interscroller ads need their own stacking context to force the background image below the ad to stop it capturing mouse events
+	'interscrollerAd',
+
 	// The content displayed by the Details component
 	'summaryDetails',