fix nested area margin collapse (#4879)

* fix nested area margin collapse

* remove test markup

Author: stuartromanek

CHANGELOG.md

@@ -20,6 +20,7 @@
 * Fixes the focus styling on AposTable headers.
 * Proper errors when widgets are badly configured in expanded mode.
 * More reliable Media Manager infinite scroll pagination.
+* Fixes margin collapse in nested areas by switching to `padding` instead of `margin`
 * Fixes Edit in Media Manager when the image is not in the currently loaded images. This may happen when the the Media Manager is in a relationship mode. 
 
 ## 4.13.0 (2025-02-19)

modules/@apostrophecms/ui/ui/apos/scss/global/_widgets.scss

@@ -1,5 +1,5 @@
 [data-apos-area] [data-apos-area] {
-  margin: var(--a-widget-margin);
+  padding: var(--a-widget-margin);
 }
 
 [data-rich-text] p:empty::after {