diff --git a/packages/edit-site/src/components/style-book/constants.ts b/packages/edit-site/src/components/style-book/constants.ts
index 84fb06f33c743e..510fa320dbc879 100644
--- a/packages/edit-site/src/components/style-book/constants.ts
+++ b/packages/edit-site/src/components/style-book/constants.ts
@@ -252,6 +252,10 @@ export const STYLE_BOOK_IFRAME_STYLES = `
 	}
 
 	.edit-site-style-book__example-preview {
+		width: 100%;
+	}
+	
+	.is-wide .edit-site-style-book__example-preview {
 		width: calc(100% - 120px);
 	}