Global Styles: Add scoping of feature level selectors for custom block style variations

lib/class-wp-theme-json-gutenberg.php

@@ -1200,7 +1200,7 @@ public function get_stylesheet( $types = array( 'variables', 'styles', 'presets'
 				$node['selector'] = static::scope_selector( $options['scope'], $node['selector'] );
 			}
 			foreach ( $style_nodes as &$node ) {
-				$node['selector'] = static::scope_selector( $options['scope'], $node['selector'] );
+				$node = static::scope_style_node_selectors( $options['scope'], $node );
 			}
 			unset( $node );
 		}
@@ -4039,4 +4039,37 @@ function ( $matches ) use ( $variation_class ) {
 
 		return implode( ',', $result );
 	}
+
+	/**
+	 * Scopes the selectors for a given style node. This includes the primary
+	 * selector, i.e. `$node['selector']`, as well as any custom selectors for
+	 * features and subfeatures, e.g. `$node['selectors']['border']` etc.
+	 *
+	 * @since 6.6.0
+	 *
+	 * @param string $scope Selector to scope to.
+	 * @param array  $node  Style node with selectors to scope.
+	 *
+	 * @return array Node with updated selectors.
+	 */
+	protected static function scope_style_node_selectors( $scope, $node ) {
+		$node['selector'] = static::scope_selector( $scope, $node['selector'] );
+
+		if ( empty( $node['selectors'] ) ) {
+			return $node;
+		}
+
+		foreach ( $node['selectors'] as $feature => $selector ) {
+			if ( is_string( $selector ) ) {
+				$node['selectors'][ $feature ] = static::scope_selector( $scope, $selector );
+			}
+			if ( is_array( $selector ) ) {
+				foreach ( $selector as $subfeature => $subfeature_selector ) {
+					$node['selectors'][ $feature ][ $subfeature ] = static::scope_selector( $scope, $subfeature_selector );
+				}
+			}
+		}
+
+		return $node;
+	}
 }