diff --git a/core/lib/Drupal/Core/Extension/ThemeHandler.php b/core/lib/Drupal/Core/Extension/ThemeHandler.php
index d9ef77e..190fe74 100644
--- a/core/lib/Drupal/Core/Extension/ThemeHandler.php
+++ b/core/lib/Drupal/Core/Extension/ThemeHandler.php
@@ -377,11 +377,11 @@ public function listInfo() {
    */
   public function addTheme(Extension $theme) {
     // @todo Remove this 100% unnecessary duplication of properties.
-    foreach ($theme->info['stylesheets'] as $media => $stylesheets) {
+    /*foreach ($theme->info['stylesheets'] as $media => $stylesheets) {
       foreach ($stylesheets as $stylesheet => $path) {
         $theme->stylesheets[$media][$stylesheet] = $path;
       }
-    }
+    }*/
     foreach ($theme->info['libraries'] as $library => $name) {
       $theme->libraries[$library] = $name;
     }
diff --git a/core/lib/Drupal/Core/Theme/ThemeInitialization.php b/core/lib/Drupal/Core/Theme/ThemeInitialization.php
index c6d800e..c8a0fc5 100644
--- a/core/lib/Drupal/Core/Theme/ThemeInitialization.php
+++ b/core/lib/Drupal/Core/Theme/ThemeInitialization.php
@@ -153,8 +153,8 @@ public function getActiveTheme(Extension $theme, array $base_themes = []) {
     // Grab stylesheets from base theme.
     $final_stylesheets = array();
     foreach ($base_themes as $base) {
-      if (!empty($base->stylesheets)) {
-        foreach ($base->stylesheets as $media => $stylesheets) {
+      if (!empty($base->info['stylesheets'])) {
+        foreach ($base->info['stylesheets'] as $media => $stylesheets) {
           foreach ($stylesheets as $name => $stylesheet) {
             $final_stylesheets[$media][$name] = $stylesheet;
           }
@@ -175,8 +175,8 @@ public function getActiveTheme(Extension $theme, array $base_themes = []) {
     }
 
     // Add stylesheets used by this theme.
-    if (!empty($theme->stylesheets)) {
-      foreach ($theme->stylesheets as $media => $stylesheets) {
+    if (!empty($theme->info['stylesheets'])) {
+      foreach ($theme->info['stylesheets'] as $media => $stylesheets) {
         foreach ($stylesheets as $name => $stylesheet) {
           $final_stylesheets[$media][$name] = $stylesheet;
         }