diff --git a/core/includes/common.inc b/core/includes/common.inc
index 88d6fd3..7b0f05d 100644
--- a/core/includes/common.inc
+++ b/core/includes/common.inc
@@ -3119,7 +3119,7 @@ function drupal_pre_render_styles($elements) {
 function drupal_build_css_cache($css) {
   $data = '';
   $uri = '';
-  $map = variable_get('drupal_css_cache_files', array());
+  $map = config('system.performance')->get('cache.css_files');
   // Create a new array so that only the file names are used to create the hash.
   // This prevents new aggregates from being created unnecessarily.
   $css_data = array();
@@ -3187,7 +3187,7 @@ function drupal_build_css_cache($css) {
     }
     // Save the updated map.
     $map[$key] = $uri;
-    variable_set('drupal_css_cache_files', $map);
+    state()->set('drupal_css_cache_files', $map);
   }
   return $uri;
 }
@@ -3352,7 +3352,7 @@ function _drupal_load_stylesheet($matches) {
  * Deletes old cached CSS files.
  */
 function drupal_clear_css_cache() {
-  variable_del('drupal_css_cache_files');
+  state()->delete('drupal_css_cache_files');
   file_scan_directory('public://css', '/.*/', array('callback' => 'drupal_delete_file_if_stale'));
 }
 
diff --git a/core/modules/color/lib/Drupal/color/Tests/ColorTest.php b/core/modules/color/lib/Drupal/color/Tests/ColorTest.php
index fea5686..9ddd06a 100644
--- a/core/modules/color/lib/Drupal/color/Tests/ColorTest.php
+++ b/core/modules/color/lib/Drupal/color/Tests/ColorTest.php
@@ -110,7 +110,7 @@ function _testColor($theme, $test_values) {
     $config->set('css.preprocess', 1);
     $config->save();
     $this->drupalGet('<front>');
-    $stylesheets = variable_get('drupal_css_cache_files', array());
+    $stylesheets = state()->get('drupal_css_cache_files') ?: array();
     $stylesheet_content = '';
     foreach ($stylesheets as $key => $uri) {
       $stylesheet_content .= join("\n", file(drupal_realpath($uri)));