diff --git a/conditional_styles.info b/conditional_styles.info
deleted file mode 100644
index 58dc80c..0000000
--- a/conditional_styles.info
+++ /dev/null
@@ -1,8 +0,0 @@
-name = "Conditional Stylesheets"
-description = "Allows themes to add conditional stylesheets."
-
-core = 7.x
-
-files[] = conditional_styles.install
-files[] = conditional_styles.module
-files[] = tests/conditional_styles.test
diff --git a/conditional_styles.info.yml b/conditional_styles.info.yml
new file mode 100644
index 0000000..b7d3d79
--- /dev/null
+++ b/conditional_styles.info.yml
@@ -0,0 +1,6 @@
+name: Conditional Stylesheets
+type: module
+description: 'Allows themes to add conditional stylesheets.'
+package: Other
+version: VERSION
+core: 8.x
diff --git a/conditional_styles.install b/conditional_styles.install
deleted file mode 100644
index b8b7a9e..0000000
--- a/conditional_styles.install
+++ /dev/null
@@ -1,19 +0,0 @@
-<?php
-/**
- * @file
- * Provides upgrade function for conditional_styles.
- */
-
-/**
- * Removes the variables used by 6.x-1.x.
- */
-function conditional_styles_update_7201() {
-  // Delete no-longer-needed conditional stylesheets variables.
-  $themes = list_themes();
-  foreach (array_keys($themes) AS $theme) {
-    variable_del('conditional_styles_' . $theme);
-    variable_del('conditional_styles_' . $theme . '_rtl');
-  }
-  // Clear the page cache.
-  cache_clear_all();
-}
diff --git a/conditional_styles.module b/conditional_styles.module
index 2d0abe7..97bb34e 100644
--- a/conditional_styles.module
+++ b/conditional_styles.module
@@ -1,40 +1,36 @@
 <?php
+
+/**
+ * @file
+ * Adds conditional CSS from the .info file.
+ */
+
 /**
- * Implements MODULE_preprocess_html(); adds conditional CSS from the .info file.
+ * Implements hook_page_build().
  */
-function conditional_styles_preprocess_html(&$vars, $hook) {
-  // Make a list of base themes and the current theme.
-  $themes = $GLOBALS['base_theme_info'];
-  $themes[] = $GLOBALS['theme_info'];
-  foreach (array_keys($themes) as $key) {
-    $theme_path = dirname($themes[$key]->filename) . '/';
-    if (isset($themes[$key]->info['stylesheets-conditional'])) {
-      foreach (array_keys($themes[$key]->info['stylesheets-conditional']) as $condition) {
-        foreach (array_keys($themes[$key]->info['stylesheets-conditional'][$condition]) as $media) {
-          foreach ($themes[$key]->info['stylesheets-conditional'][$condition][$media] as $stylesheet) {
-            // Add each conditional stylesheet.
-            drupal_add_css(
-              $theme_path . $stylesheet,
-              array(
-                'group' => CSS_THEME,
-                'browsers' => array(
-                  'IE' => $condition,
-                  '!IE' => strpos($condition, '!IE') === FALSE ? FALSE : TRUE,
-                ),
-                'weight' => 999,
-                'every_page' => TRUE,
-              )
-            );
-          }
+function conditional_styles_page_build(&$page) {
+  $theme_handler = \Drupal::service('theme_handler');
+  $themes        = $theme_handler->listInfo(); 
+  foreach ($themes as $theme) {
+    $theme_path = drupal_get_path($theme->type, $theme->name);
+    if (isset($theme->info['stylesheets-conditional']) && $theme->status) {
+      foreach ($theme->info['stylesheets-conditional'] as $condition => $medias) {
+        foreach ($medias as $media => $stylesheets) {
+	        foreach ($stylesheets as $stylesheet) {
+	        	$full_path = $theme_path . '/' . $stylesheet;
+	          $page['#attached']['css'][$full_path] = array(
+          		'group' => CSS_THEME,
+          		'weight' => 999,
+          		'media' => $media,
+          		'every_page' => TRUE,
+              'browsers' => array(
+                'IE'  => $condition,
+                '!IE' => strpos($condition, '!IE') === FALSE ? FALSE : TRUE,
+              ),
+	          );
+	        }
         }
       }
     }
   }
 }
-
-/**
- * Implements MODULE_preprocess_maintenance_page().
- */
-function conditional_styles_preprocess_maintenance_page(&$vars, $hook) {
-  conditional_styles_preprocess_html($vars, $hook);
-}
diff --git a/tests/conditional_styles.test b/tests/conditional_styles.test
deleted file mode 100644
index d3087cf..0000000
--- a/tests/conditional_styles.test
+++ /dev/null
@@ -1,50 +0,0 @@
-<?php
-/**
- * @file
- * Tests for conditional stylesheets.
- */
-
-/**
- * Test the Conditional Stylesheets module.
- */
-class ConditionalStylesheetsTestCase extends DrupalWebTestCase {
-  public static function getInfo() {
-    return array(
-      'name' => 'Conditional stylesheets',
-      'description' => 'Tests adding conditional stylesheets via a .info file.',
-      'group' => 'Conditional Stylesheets',
-    );
-  }
-
-  function setUp() {
-    parent::setUp('conditional_styles_test');
-  }
-
-  /**
-   * Test that stylesheets in theme .info files are loaded.
-   */
-  function testThemeInfo() {
-    theme_enable(array('conditional_styles_subtheme'));
-    variable_set('theme_default', 'conditional_styles_subtheme');
-
-    $this->drupalGet('');
-
-    // Verify sub-style.css is in an IE conditional comment.
-    $pattern = '/<!--\[if\ gte\ IE\ 1\]>.*sub\-style\.css.*<!\[endif\]-->/simx';
-    $this->assertPattern($pattern, t('Conditional stylesheet added via theme .info file was found.'));
-  }
-
-  /**
-   * Test that stylesheets in base theme .info files are loaded.
-   */
-  function testBaseThemeInfo() {
-    theme_enable(array('conditional_styles_subtheme'));
-    variable_set('theme_default', 'conditional_styles_subtheme');
-
-    $this->drupalGet('');
-
-    // Verify base-style.css is in an IE conditional comment.
-    $pattern = '/<!--\[if\ gte\ IE\ 1\]>.*base\-style\.css.*<!\[endif\]-->/simx';
-    $this->assertPattern($pattern, t('Conditional stylesheet added via base theme .info file was found.'));
-  }
-}
diff --git a/tests/conditional_styles_basetheme/base-style.css b/tests/conditional_styles_basetheme/base-style.css
deleted file mode 100644
index b34a570..0000000
--- a/tests/conditional_styles_basetheme/base-style.css
+++ /dev/null
@@ -1 +0,0 @@
-/* base theme styles */
diff --git a/tests/conditional_styles_basetheme/conditional_styles_basetheme.info b/tests/conditional_styles_basetheme/conditional_styles_basetheme.info
deleted file mode 100644
index 12aff7e..0000000
--- a/tests/conditional_styles_basetheme/conditional_styles_basetheme.info
+++ /dev/null
@@ -1,6 +0,0 @@
-name = Conditional stylesheets test base theme
-description = Test theme which acts as a base theme for other test subthemes.
-
-hidden = TRUE
-
-stylesheets-conditional[gte IE 1]['all'][] = base-style.css
diff --git a/tests/conditional_styles_subtheme/conditional_styles_subtheme.info b/tests/conditional_styles_subtheme/conditional_styles_subtheme.info
deleted file mode 100644
index 0612e5e..0000000
--- a/tests/conditional_styles_subtheme/conditional_styles_subtheme.info
+++ /dev/null
@@ -1,7 +0,0 @@
-name = Conditional stylesheets test sub-theme
-description = Test theme which uses update_test_basetheme as the base theme.
-
-base theme = conditional_styles_basetheme
-hidden = TRUE
-
-stylesheets-conditional[gte IE 1]['all'][] = sub-style.css
diff --git a/tests/conditional_styles_subtheme/sub-style.css b/tests/conditional_styles_subtheme/sub-style.css
deleted file mode 100644
index 39ca15b..0000000
--- a/tests/conditional_styles_subtheme/sub-style.css
+++ /dev/null
@@ -1 +0,0 @@
-/* sub-theme styles */
diff --git a/tests/conditional_styles_test.info b/tests/conditional_styles_test.info
deleted file mode 100644
index 94fd1ec..0000000
--- a/tests/conditional_styles_test.info
+++ /dev/null
@@ -1,8 +0,0 @@
-name = "Conditional Stylesheets Tests"
-package = Testing
-
-core = 7.x
-hidden = TRUE
-dependencies[] = conditional_styles
-
-files[] = conditional_styles_test.module
diff --git a/tests/conditional_styles_test.module b/tests/conditional_styles_test.module
deleted file mode 100644
index 08d3f46..0000000
--- a/tests/conditional_styles_test.module
+++ /dev/null
@@ -1,14 +0,0 @@
-<?php
-/**
- * @file
- * Test module for conditional stylesheets.
- */
-
-/**
- * Implements hook_system_theme_info().
- */
-function conditional_styles_test_system_theme_info() {
-  $themes['conditional_styles_basetheme'] = drupal_get_path('module', 'conditional_styles') . '/tests/conditional_styles_basetheme/conditional_styles_basetheme.info';
-  $themes['conditional_styles_subtheme'] = drupal_get_path('module', 'conditional_styles') . '/tests/conditional_styles_subtheme/conditional_styles_subtheme.info';
-  return $themes;
-}