#3437099 made sure the css file is loaded below the theme.

modules/browser_development_assist/browser_development_assist.module

@@ -7,6 +7,7 @@
 
 use Drupal\browser_development_assist\Processing\FileSystemStructure;
 use Drupal\Core\Routing\RouteMatchInterface;
+use Drupal\Core\Asset\AttachedAssetsInterface;
 
 /**
  * Implements hook_help().
@@ -27,20 +28,6 @@ function browser_development_assist_help($route_name, RouteMatchInterface $route
   }
 }
 
-/**
- * Implements hook_page_attachments().
- */
-function browser_development_assist_page_attachments(array &$page) {
-
-  // Attaching library to theme
-  $active = \Drupal::theme()->getActiveTheme()->getName();
-  $current_theme = \Drupal::config('system.theme')->get('default');
-  if ($active === $current_theme) {
-    $page['#attached']['library'][] =  'browser_development_assist/browser-development-assist';
-  }
-}
-
-
 /**
  * Implements hook_library_info_build().
  */
@@ -53,10 +40,43 @@ function browser_development_assist_library_info_build() {
       'version' => 'VERSION',
       'css' => [
         'theme' => [
-          "$css" => ['weight' => '100']
+          "$css" => []
         ] 
       ],
     ],
   ];
 }
 
+/**
+ * Attaches 
+ * 
+ * Implements hook_page_attachments().
+ */
+function browser_development_assist_page_attachments(array &$page) {
+
+  // Attaching library to theme
+  $active = \Drupal::theme()->getActiveTheme()->getName();
+  $current_theme = \Drupal::config('system.theme')->get('default');
+  if ($active === $current_theme) {
+    $page['#attached']['library'][] =  'browser_development_assist/browser-development-assist';
+  }
+}
+
+
+
+
+
+/**
+ * Implements hook_css_alter().
+ */
+function browser_development_assist_css_alter(&$css, AttachedAssetsInterface $assets) {
+
+  $library = \Drupal::service('library.discovery')
+    ->getLibraryByName('browser_development_assist', 'browser-development-assist');
+  
+  $path = $library['css'][0]['data'];
+
+  if (isset($css[$path])) {
+    $css[$path]['group'] = 300;
+  }
+}