Blockbase: avoid margin-top on the first paragraph child of a group

blockbase/assets/ponyfill.css

@@ -514,7 +514,7 @@ input[type=checkbox] + label {
   flex-wrap: nowrap;
 }
 .wp-block-navigation.blockbase-responsive-navigation-minimal.is-responsive .is-menu-open.wp-block-navigation__responsive-container .wp-block-navigation__responsive-container-content .wp-block-navigation-item {
-  row-gap: 0rem;
+  row-gap: 0;
 }
 .wp-block-navigation.blockbase-responsive-navigation-minimal.is-responsive .is-menu-open.wp-block-navigation__responsive-container .wp-block-navigation__responsive-container-content .wp-block-navigation-item > a:hover {
   -webkit-text-decoration-line: underline;
@@ -593,7 +593,7 @@ input[type=checkbox] + label {
   flex-direction: column;
 }
 
-p.has-drop-cap:not(:focus):first-letter {
+p.has-drop-cap:not(:focus)::first-letter {
   font-size: var(--wp--custom--paragraph--dropcap--typography--font-size);
   font-weight: var(--wp--custom--paragraph--dropcap--typography--font-weight);
   margin: var(--wp--custom--paragraph--dropcap--margin);
@@ -740,7 +740,7 @@ p.has-drop-cap:not(:focus):first-letter {
 .wp-block-post-content p.wp-block.wp-block-paragraph,
 .wp-block-post-content *[class^=wp-container] > * + p,
 .wp-block-post-content *[class^=wp-container] > p + *,
-.wp-block-post-content p {
+.wp-block-post-content p:not(.wp-block-group > p) {
   margin-top: 1em;
 }
 

blockbase/sass/blocks/_post-content.scss

@@ -3,7 +3,7 @@
 	p.wp-block.wp-block-paragraph, // This selector has been made extra specific to override the block gap being set in the editor.
 	*[class^="wp-container"] > * + p,
 	*[class^="wp-container"] > p + *,
-	p {
+	p:not(.wp-block-group > p) {
 		margin-top: 1em;
 	}
 }