Update custom CSS handling to be consistent with block global styles.

src/wp-includes/block-editor.php

@@ -532,7 +532,7 @@ function get_block_editor_settings( array $custom_settings, $block_editor_contex
 		 * entered by users does not break other global styles.
 		 */
 		$global_styles[] = array(
-			'css'            => wp_get_global_styles_custom_css(),
+			'css'            => wp_get_global_stylesheet( array( 'custom-css' ) ),
 			'__unstableType' => 'user',
 			'isGlobalStyles' => true,
 		);

src/wp-includes/class-wp-theme-json.php

@@ -1423,6 +1423,12 @@ public function get_stylesheet( $types = array( 'variables', 'styles', 'presets'
 			$stylesheet .= $this->get_preset_classes( $setting_nodes, $origins );
 		}
 
+		// Load the custom CSS last so it has the highest specificity.
+		if ( in_array( 'custom-css', $types, true ) ) {
+			// Add the global styles root CSS.
+			$stylesheet .= _wp_array_get( $this->theme_json, array( 'styles', 'css' ) );
+		}
+
 		return $stylesheet;
 	}
 
@@ -2692,6 +2698,7 @@ private static function get_block_nodes( $theme_json, $selectors = array(), $opt
 				'duotone'    => $duotone_selector,
 				'features'   => $feature_selectors,
 				'variations' => $variation_selectors,
+				'css'        => $selector,
 			);
 
 			if ( isset( $theme_json['styles']['blocks'][ $name ]['elements'] ) ) {
@@ -2913,6 +2920,11 @@ static function ( $pseudo_selector ) use ( $selector ) {
 			$block_rules .= $this->process_blocks_custom_css( $node['css'], $selector );
 		}
 
+		// 7. Generate and append any custom CSS rules.
+		if ( isset( $node['css'] ) ) {
+			$block_rules .= $this->process_blocks_custom_css( $node['css'], $selector );
+		}
+
 		return $block_rules;
 	}
 

src/wp-includes/default-filters.php

@@ -600,9 +600,6 @@
 add_action( 'wp_enqueue_scripts', 'wp_enqueue_global_styles' );
 add_action( 'wp_footer', 'wp_enqueue_global_styles', 1 );
 
-// Global styles custom CSS.
-add_action( 'wp_enqueue_scripts', 'wp_enqueue_global_styles_custom_css' );
-
 // Block supports, and other styles parsed and stored in the Style Engine.
 add_action( 'wp_enqueue_scripts', 'wp_enqueue_stored_styles' );
 add_action( 'wp_footer', 'wp_enqueue_stored_styles', 1 );

src/wp-includes/script-loader.php

@@ -2504,6 +2504,18 @@ function wp_enqueue_global_styles() {
 
 	$stylesheet = wp_get_global_stylesheet();
 
+	/*
+	 * Dequeue the Customizer's custom CSS
+	 * and add it before the global styles custom CSS.
+	 */
+	remove_action( 'wp_head', 'wp_custom_css_cb', 101 );
+	// Get the custom CSS from the Customizer and add it to the global stylesheet.
+	$custom_css  = wp_get_custom_css();
+	$stylesheet .= $custom_css;
+
+	// Add the global styles custom CSS at the end.
+	$stylesheet .= wp_get_global_stylesheet( array( 'custom-css' ) );
+
 	if ( empty( $stylesheet ) ) {
 		return;
 	}