From e48e5ce2f3799b9a892608993dd279ddab9e722f Mon Sep 17 00:00:00 2001
From: Kite <ixkaito@gmail.com>
Date: Sat, 5 Feb 2022 19:52:44 +0900
Subject: [PATCH] Remove margins of root container for classic themes to
 prevent vertical expanding and horizontal scrollbars

---
 packages/edit-post/src/classic.scss | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/packages/edit-post/src/classic.scss b/packages/edit-post/src/classic.scss
index 8cba8020e0b912..132e4603959f74 100644
--- a/packages/edit-post/src/classic.scss
+++ b/packages/edit-post/src/classic.scss
@@ -18,6 +18,20 @@ html :where(.editor-styles-wrapper) {
 	}
 }
 
+.block-editor-block-preview__content-iframe {
+	.block-editor-block-list__layout.is-root-container > .wp-block {
+		// Prevent full-height blocks expanding height endlessly in pattern preview.
+		margin-top: 0;
+		margin-bottom: 0;
+
+		// Remove the compensating margin of full-wide blocks in pattern preview to prevent horizontal scrollbars.
+		&[data-align="full"] {
+			margin-left: 0;
+			margin-right: 0;
+		}
+	}
+}
+
 // Deprecated style needed for the block widths and alignments.
 // for themes that don't support the new layout (theme.json).
 html :where(.wp-block) {