diff --git a/core/modules/book/book.module b/core/modules/book/book.module
index a94b8f2..cf34c20 100644
--- a/core/modules/book/book.module
+++ b/core/modules/book/book.module
@@ -337,7 +337,7 @@ function book_form_node_form_alter(&$form, &$form_state, $form_id) {
       '#submit' => array('book_pick_book_nojs_submit'),
       '#weight' => 20,
       '#attached' => array(
-        'css' => array(drupal_get_path('module', 'book') . '/book.admin.css'),
+        'css' => array(drupal_get_path('module', 'book') . '/css/book.admin.css'),
       ),
     );
   }
@@ -999,7 +999,7 @@ function template_preprocess_book_all_books_block(&$variables) {
  * @see book-navigation.tpl.php
  */
 function template_preprocess_book_navigation(&$variables) {
-  drupal_add_css(drupal_get_path('module', 'book') . '/book.theme.css');
+  drupal_add_css(drupal_get_path('module', 'book') . '/css/book.theme.css');
   $book_link = $variables['book_link'];
 
   // Provide extra variables for themers. Not needed by default.
diff --git a/core/modules/book/book.admin.css b/core/modules/book/css/book.admin.css
similarity index 100%
rename from core/modules/book/book.admin.css
rename to core/modules/book/css/book.admin.css
diff --git a/core/modules/book/book.theme-rtl.css b/core/modules/book/css/book.theme-rtl.css
similarity index 100%
rename from core/modules/book/book.theme-rtl.css
rename to core/modules/book/css/book.theme-rtl.css
diff --git a/core/modules/book/book.theme.css b/core/modules/book/css/book.theme.css
similarity index 100%
rename from core/modules/book/book.theme.css
rename to core/modules/book/css/book.theme.css
diff --git a/core/modules/comment/comment.theme-rtl.css b/core/modules/comment/css/comment.theme-rtl.css
similarity index 100%
rename from core/modules/comment/comment.theme-rtl.css
rename to core/modules/comment/css/comment.theme-rtl.css
diff --git a/core/modules/comment/comment.theme.css b/core/modules/comment/css/comment.theme.css
similarity index 100%
rename from core/modules/comment/comment.theme.css
rename to core/modules/comment/css/comment.theme.css
diff --git a/core/modules/comment/lib/Drupal/comment/CommentRenderController.php b/core/modules/comment/lib/Drupal/comment/CommentRenderController.php
index dab8dc4..c6b21f0 100644
--- a/core/modules/comment/lib/Drupal/comment/CommentRenderController.php
+++ b/core/modules/comment/lib/Drupal/comment/CommentRenderController.php
@@ -86,7 +86,7 @@ protected function alterBuild(array &$build, EntityInterface $comment, EntityDis
 
       // Add indentation div or close open divs as needed.
       if ($is_threaded) {
-        $build['#attached']['css'][] = drupal_get_path('module', 'comment') . '/comment.theme.css';
+        $build['#attached']['css'][] = drupal_get_path('module', 'comment') . '/css/comment.theme.css';
         $prefix .= $comment->divs <= 0 ? str_repeat('</div>', abs($comment->divs)) : "\n" . '<div class="indented">';
       }
 
diff --git a/core/modules/contextual/contextual.module b/core/modules/contextual/contextual.module
index 51747c6..9971fd2 100644
--- a/core/modules/contextual/contextual.module
+++ b/core/modules/contextual/contextual.module
@@ -85,8 +85,8 @@ function contextual_library_info() {
       $path . '/contextual.js' => array('group' => JS_LIBRARY, 'weight' => -2),
     ),
     'css' => array(
-      $path . '/contextual.base.css' => array(),
-      $path . '/contextual.theme.css' => array(),
+      $path . '/css/contextual.module.css' => array(),
+      $path . '/css/contextual.theme.css' => array(),
     ),
     'dependencies' => array(
       array('system', 'jquery'),
@@ -106,7 +106,7 @@ function contextual_library_info() {
       $path . '/contextual.toolbar.js' => array('group' => JS_LIBRARY, 'weight' => -1),
     ),
     'css' => array(
-      $path . '/contextual.toolbar.css' => array(),
+      $path . '/css/contextual.toolbar.css' => array(),
     ),
     'dependencies' => array(
       array('system', 'jquery'),
diff --git a/core/modules/contextual/contextual.base.css b/core/modules/contextual/css/contextual.module.css
similarity index 100%
rename from core/modules/contextual/contextual.base.css
rename to core/modules/contextual/css/contextual.module.css
diff --git a/core/modules/contextual/contextual.theme-rtl.css b/core/modules/contextual/css/contextual.theme-rtl.css
similarity index 100%
rename from core/modules/contextual/contextual.theme-rtl.css
rename to core/modules/contextual/css/contextual.theme-rtl.css
diff --git a/core/modules/contextual/contextual.theme.css b/core/modules/contextual/css/contextual.theme.css
similarity index 100%
rename from core/modules/contextual/contextual.theme.css
rename to core/modules/contextual/css/contextual.theme.css
diff --git a/core/modules/contextual/contextual.toolbar-rtl.css b/core/modules/contextual/css/contextual.toolbar-rtl.css
similarity index 100%
rename from core/modules/contextual/contextual.toolbar-rtl.css
rename to core/modules/contextual/css/contextual.toolbar-rtl.css
diff --git a/core/modules/contextual/contextual.toolbar.css b/core/modules/contextual/css/contextual.toolbar.css
similarity index 100%
rename from core/modules/contextual/contextual.toolbar.css
rename to core/modules/contextual/css/contextual.toolbar.css
diff --git a/core/modules/edit/css/edit.css b/core/modules/edit/css/edit.module.css
similarity index 100%
rename from core/modules/edit/css/edit.css
rename to core/modules/edit/css/edit.module.css
diff --git a/core/modules/edit/edit.module b/core/modules/edit/edit.module
index 0c8eb0f..9d98ef5 100644
--- a/core/modules/edit/edit.module
+++ b/core/modules/edit/edit.module
@@ -100,7 +100,7 @@ function edit_library_info() {
       ),
     ),
     'css' => array(
-      $path . '/css/edit.css' => array(),
+      $path . '/css/edit.module.css' => array(),
     ),
     'dependencies' => array(
       array('system', 'jquery'),
diff --git a/core/modules/field/theme/field-rtl.css b/core/modules/field/css/field.module-rtl.css
similarity index 100%
rename from core/modules/field/theme/field-rtl.css
rename to core/modules/field/css/field.module-rtl.css
diff --git a/core/modules/field/theme/field.css b/core/modules/field/css/field.module.css
similarity index 100%
rename from core/modules/field/theme/field.css
rename to core/modules/field/css/field.module.css
diff --git a/core/modules/field/field.module b/core/modules/field/field.module
index 8f459a3..f5a1e5b 100644
--- a/core/modules/field/field.module
+++ b/core/modules/field/field.module
@@ -999,7 +999,7 @@ function field_extract_bundle($entity_type, $bundle) {
  */
 function field_page_build(&$page) {
   $path = drupal_get_path('module', 'field');
-  $page['#attached']['css'][$path . '/theme/field.css'] = array('every_page' => TRUE);
+  $page['#attached']['css'][$path . '/css/field.module.css'] = array('every_page' => TRUE);
 }
 
 /**
@@ -1044,7 +1044,7 @@ function template_preprocess_field(&$variables, $hook) {
     'field-label-' . $element['#label_display'],
   );
   // Add a "clearfix" class to the wrapper since we float the label and the
-  // field items in field.css if the label is inline.
+  // field items in field.module.css if the label is inline.
   if ($element['#label_display'] == 'inline') {
     $variables['attributes']['class'][] = 'clearfix';
   }
diff --git a/core/modules/forum/forum-rtl.css b/core/modules/forum/css/forum.module-rtl.css
similarity index 100%
rename from core/modules/forum/forum-rtl.css
rename to core/modules/forum/css/forum.module-rtl.css
diff --git a/core/modules/forum/forum.css b/core/modules/forum/css/forum.module.css
similarity index 93%
rename from core/modules/forum/forum.css
rename to core/modules/forum/css/forum.module.css
index 5ac5e75..0c4f8fc 100644
--- a/core/modules/forum/forum.css
+++ b/core/modules/forum/css/forum.module.css
@@ -16,7 +16,7 @@
   white-space: nowrap;
 }
 #forum .icon{
-  background-image: url(../../misc/forum-icons.png);
+  background-image: url(../../../misc/forum-icons.png);
   background-repeat: no-repeat;
   float: left; /* LTR */
   height: 24px;
diff --git a/core/modules/forum/forum.pages.inc b/core/modules/forum/forum.pages.inc
index 422d92e..652f39e 100644
--- a/core/modules/forum/forum.pages.inc
+++ b/core/modules/forum/forum.pages.inc
@@ -73,6 +73,6 @@ function forum_page($forum_term = NULL) {
     '#sortby' => $sort_by,
     '#forums_per_page' => $forum_per_page,
   );
-  $build['#attached']['css'][] = drupal_get_path('module', 'forum') . '/forum.css';
+  $build['#attached']['css'][] = drupal_get_path('module', 'forum') . '/css/forum.css';
   return $build;
 }
diff --git a/core/modules/help/help-rtl.css b/core/modules/help/css/help.module-rtl.css
similarity index 100%
rename from core/modules/help/help-rtl.css
rename to core/modules/help/css/help.module-rtl.css
diff --git a/core/modules/help/help.css b/core/modules/help/css/help.module.css
similarity index 100%
rename from core/modules/help/help.css
rename to core/modules/help/css/help.module.css
diff --git a/core/modules/help/lib/Drupal/help/Controller/HelpController.php b/core/modules/help/lib/Drupal/help/Controller/HelpController.php
index 118f1bc..9533a45 100644
--- a/core/modules/help/lib/Drupal/help/Controller/HelpController.php
+++ b/core/modules/help/lib/Drupal/help/Controller/HelpController.php
@@ -47,7 +47,7 @@ public static function create(ContainerInterface $container) {
    */
   public function helpMain() {
     // Add CSS.
-    drupal_add_css(drupal_get_path('module', 'help') . '/help.css');
+    drupal_add_css(drupal_get_path('module', 'help') . '/css/help.module.css');
     $output = '<h2>' . t('Help topics') . '</h2><p>' . t('Help is available on the following items:') . '</p>' . $this->helpLinksAsList();
     return $output;
   }
diff --git a/core/modules/help/lib/Drupal/help/Tests/HelpTest.php b/core/modules/help/lib/Drupal/help/Tests/HelpTest.php
index 54b955f..5a40fa0 100644
--- a/core/modules/help/lib/Drupal/help/Tests/HelpTest.php
+++ b/core/modules/help/lib/Drupal/help/Tests/HelpTest.php
@@ -67,7 +67,7 @@ public function testHelp() {
     // Check for css on admin/help.
     $this->drupalLogin($this->adminUser);
     $this->drupalGet('admin/help');
-    $this->assertRaw(drupal_get_path('module', 'help') . '/help.css', 'The help.css file is present in the HTML.');
+    $this->assertRaw(drupal_get_path('module', 'help') . '/css/help.module.css', 'The help.module.css file is present in the HTML.');
 
     // Verify that introductory help text exists, goes for 100% module coverage.
     $this->assertRaw(t('For more information, refer to the specific topics listed in the next section or to the <a href="@drupal">online Drupal handbooks</a>.', array('@drupal' => 'http://drupal.org/documentation')), 'Help intro text correctly appears.');
diff --git a/core/modules/image/image.admin.css b/core/modules/image/css/image.admin.css
similarity index 100%
rename from core/modules/image/image.admin.css
rename to core/modules/image/css/image.admin.css
diff --git a/core/modules/image/image.theme-rtl.css b/core/modules/image/css/image.skin-rtl.css
similarity index 100%
rename from core/modules/image/image.theme-rtl.css
rename to core/modules/image/css/image.skin-rtl.css
diff --git a/core/modules/image/image.theme.css b/core/modules/image/css/image.skin.css
similarity index 100%
rename from core/modules/image/image.theme.css
rename to core/modules/image/css/image.skin.css
diff --git a/core/modules/image/image.admin.inc b/core/modules/image/image.admin.inc
index 9ed3aa9..5963933 100644
--- a/core/modules/image/image.admin.inc
+++ b/core/modules/image/image.admin.inc
@@ -39,7 +39,7 @@ function image_style_form($form, &$form_state, $style) {
 
   $form_state['image_style'] = $style;
   $form['#tree'] = TRUE;
-  $form['#attached']['css'][drupal_get_path('module', 'image') . '/image.admin.css'] = array();
+  $form['#attached']['css'][drupal_get_path('module', 'image') . '/css/image.admin.css'] = array();
 
   // Show the thumbnail preview.
   $form['preview'] = array(
@@ -297,7 +297,7 @@ function image_effect_form($form, &$form_state, $style, $effect) {
   }
   drupal_set_title($title, PASS_THROUGH);
 
-  $form['#attached']['css'][drupal_get_path('module', 'image') . '/image.admin.css'] = array();
+  $form['#attached']['css'][drupal_get_path('module', 'image') . '/css/image.admin.css'] = array();
 
   $form['ieid'] = array(
     '#type' => 'value',
diff --git a/core/modules/image/image.field.inc b/core/modules/image/image.field.inc
index a287620..37bedca 100644
--- a/core/modules/image/image.field.inc
+++ b/core/modules/image/image.field.inc
@@ -316,7 +316,7 @@ function image_field_widget_process($element, &$form_state, $form) {
   $item['fids'] = $element['fids']['#value'];
 
   $element['#theme'] = 'image_widget';
-  $element['#attached']['css'][] = drupal_get_path('module', 'image') . '/image.theme.css';
+  $element['#attached']['css'][] = drupal_get_path('module', 'image') . '/css/image.theme.css';
 
   // Add the image preview.
   if (!empty($element['#files']) && $element['#preview_image_style']) {
diff --git a/core/modules/node/node.admin.css b/core/modules/node/css/node.admin.css
similarity index 100%
rename from core/modules/node/node.admin.css
rename to core/modules/node/css/node.admin.css
diff --git a/core/modules/node/node.edit.admin.css b/core/modules/node/css/node.module.css
similarity index 100%
rename from core/modules/node/node.edit.admin.css
rename to core/modules/node/css/node.module.css
diff --git a/core/modules/node/node.pages.inc b/core/modules/node/node.pages.inc
index 863babd..89ca8f7 100644
--- a/core/modules/node/node.pages.inc
+++ b/core/modules/node/node.pages.inc
@@ -300,7 +300,7 @@ function node_revision_overview($node) {
     '#rows' => $rows,
     '#header' => $header,
     '#attached' => array (
-      'css' => array(drupal_get_path('module', 'node') . '/node.admin.css'),
+      'css' => array(drupal_get_path('module', 'node') . '/css/node.admin.css'),
     ),
   );
 
diff --git a/core/modules/openid/openid-rtl.css b/core/modules/openid/css/openid-rtl.module.css
similarity index 100%
rename from core/modules/openid/openid-rtl.css
rename to core/modules/openid/css/openid-rtl.module.css
diff --git a/core/modules/openid/openid.css b/core/modules/openid/css/openid.module.css
similarity index 100%
rename from core/modules/openid/openid.css
rename to core/modules/openid/css/openid.module.css
diff --git a/core/modules/openid/openid.module b/core/modules/openid/openid.module
index ad4da7b..cb96897 100644
--- a/core/modules/openid/openid.module
+++ b/core/modules/openid/openid.module
@@ -1125,7 +1125,7 @@ function openid_library_info() {
       drupal_get_path('module', 'openid') . '/openid.js' => array(),
     ),
     'css' => array(
-      drupal_get_path('module', 'openid') . '/openid.css' => array(),
+      drupal_get_path('module', 'openid') . '/css/openid.css' => array(),
     ),
     'dependencies' => array(
       array('system', 'jquery'),
diff --git a/core/modules/openid/openid.pages.inc b/core/modules/openid/openid.pages.inc
index 81a5905..5399181 100644
--- a/core/modules/openid/openid.pages.inc
+++ b/core/modules/openid/openid.pages.inc
@@ -28,7 +28,7 @@ function openid_authentication_page() {
  */
 function openid_user_identities($account) {
   drupal_set_title(user_format_name($account));
-  drupal_add_css(drupal_get_path('module', 'openid') . '/openid.css');
+  drupal_add_css(drupal_get_path('module', 'openid') . '/css/openid.css');
 
   // Check to see if we got a response
   $response = openid_complete();
diff --git a/core/modules/shortcut/shortcut.base-rtl.css b/core/modules/shortcut/css/shortcut.module-rtl.css
similarity index 100%
rename from core/modules/shortcut/shortcut.base-rtl.css
rename to core/modules/shortcut/css/shortcut.module-rtl.css
diff --git a/core/modules/shortcut/shortcut.base.css b/core/modules/shortcut/css/shortcut.module.css
similarity index 100%
rename from core/modules/shortcut/shortcut.base.css
rename to core/modules/shortcut/css/shortcut.module.css
diff --git a/core/modules/shortcut/shortcut.theme-rtl.css b/core/modules/shortcut/css/shortcut.theme-rtl.css
similarity index 100%
rename from core/modules/shortcut/shortcut.theme-rtl.css
rename to core/modules/shortcut/css/shortcut.theme-rtl.css
diff --git a/core/modules/shortcut/shortcut.theme.css b/core/modules/shortcut/css/shortcut.theme.css
similarity index 83%
rename from core/modules/shortcut/shortcut.theme.css
rename to core/modules/shortcut/css/shortcut.theme.css
index 04f7c9f..2a1a6ab 100644
--- a/core/modules/shortcut/shortcut.theme.css
+++ b/core/modules/shortcut/css/shortcut.theme.css
@@ -7,11 +7,11 @@
  * Toolbar.
  */
 .icon-shortcut:before {
-  background-image: url("images/shortcut.png");
+  background-image: url("../images/shortcut.png");
 }
 .icon-shortcut:active:before,
 .icon-shortcut.active:before {
-  background-image: url("images/shortcut-active.png");
+  background-image: url("../images/shortcut-active.png");
 }
 .toolbar .tray.horizontal.shortcuts .menu {
   float: left;
@@ -31,7 +31,7 @@
  * Add/remove links.
  */
 .add-or-remove-shortcuts .icon {
-  background: transparent url(shortcut.png) no-repeat;
+  background: transparent url(../shortcut.png) no-repeat;
   height: 12px;
   margin-left: 8px; /* LTR */
   overflow: hidden;
diff --git a/core/modules/shortcut/shortcut.module b/core/modules/shortcut/shortcut.module
index c2c9b4a..d7dc727 100644
--- a/core/modules/shortcut/shortcut.module
+++ b/core/modules/shortcut/shortcut.module
@@ -505,8 +505,8 @@ function shortcut_preprocess_page(&$variables) {
       $variables['title_suffix']['add_or_remove_shortcut'] = array(
         '#attached' => array(
           'css' => array(
-            drupal_get_path('module', 'shortcut') . '/shortcut.base.css',
-            drupal_get_path('module', 'shortcut') . '/shortcut.theme.css',
+            drupal_get_path('module', 'shortcut') . '/css/shortcut.module.css',
+            drupal_get_path('module', 'shortcut') . '/css/shortcut.theme.css',
           ),
         ),
         '#prefix' => '<div class="add-or-remove-shortcuts ' . $link_mode . '-shortcut">',
@@ -558,8 +558,8 @@ function shortcut_toolbar() {
       '#weight' => -10,
       '#attached' => array(
         'css' => array(
-          drupal_get_path('module', 'shortcut') . '/shortcut.base.css',
-          drupal_get_path('module', 'shortcut') . '/shortcut.theme.css',
+          drupal_get_path('module', 'shortcut') . '/css/shortcut.module.css',
+          drupal_get_path('module', 'shortcut') . '/css/shortcut.theme.css',
         ),
       ),
     );
diff --git a/core/modules/simpletest/simpletest.css b/core/modules/simpletest/css/simpletest.module.css
similarity index 100%
rename from core/modules/simpletest/simpletest.css
rename to core/modules/simpletest/css/simpletest.module.css
diff --git a/core/modules/simpletest/lib/Drupal/simpletest/Form/SimpletestResultsForm.php b/core/modules/simpletest/lib/Drupal/simpletest/Form/SimpletestResultsForm.php
index 35be854..a66b0a7 100644
--- a/core/modules/simpletest/lib/Drupal/simpletest/Form/SimpletestResultsForm.php
+++ b/core/modules/simpletest/lib/Drupal/simpletest/Form/SimpletestResultsForm.php
@@ -97,7 +97,7 @@ public function buildForm(array $form, array &$form_state, $test_id = NULL) {
     }
 
     // Load all classes and include CSS.
-    $form['#attached']['css'][] = drupal_get_path('module', 'simpletest') . '/simpletest.css';
+    $form['#attached']['css'][] = drupal_get_path('module', 'simpletest') . '/css/simpletest.module.css';
 
     // Keep track of which test cases passed or failed.
     $filter = array(
diff --git a/core/modules/simpletest/simpletest.module b/core/modules/simpletest/simpletest.module
index 97caa11..6ce09e8 100644
--- a/core/modules/simpletest/simpletest.module
+++ b/core/modules/simpletest/simpletest.module
@@ -157,7 +157,7 @@ function simpletest_run_tests($test_list, $reporter = 'drupal') {
     ),
     'finished' => '_simpletest_batch_finished',
     'progress_message' => '',
-    'css' => array(drupal_get_path('module', 'simpletest') . '/simpletest.css'),
+    'css' => array(drupal_get_path('module', 'simpletest') . '/css/simpletest.module.css'),
     'init_message' => t('Processing test @num of @max - %test.', array('%test' => $info['name'], '@num' => '1', '@max' => count($test_list))),
   );
   batch_set($batch);
@@ -695,7 +695,7 @@ function simpletest_library_info() {
       drupal_get_path('module', 'simpletest') . '/simpletest.js' => array(),
     ),
     'css' => array(
-      drupal_get_path('module', 'simpletest') . '/simpletest.css' => array(),
+      drupal_get_path('module', 'simpletest') . '/css/simpletest.module.css' => array(),
     ),
     'dependencies' => array(
       array('system', 'jquery'),
diff --git a/core/modules/taxonomy/taxonomy.css b/core/modules/taxonomy/css/taxonomy.module.css
similarity index 100%
rename from core/modules/taxonomy/taxonomy.css
rename to core/modules/taxonomy/css/taxonomy.module.css
diff --git a/core/modules/taxonomy/lib/Drupal/taxonomy/TermRenderController.php b/core/modules/taxonomy/lib/Drupal/taxonomy/TermRenderController.php
index 4b6c60f..e7f8882 100644
--- a/core/modules/taxonomy/lib/Drupal/taxonomy/TermRenderController.php
+++ b/core/modules/taxonomy/lib/Drupal/taxonomy/TermRenderController.php
@@ -53,7 +53,7 @@ protected function getBuildDefaults(EntityInterface $entity, $view_mode, $langco
    */
   protected function alterBuild(array &$build, EntityInterface $entity, EntityDisplay $display, $view_mode, $langcode = NULL) {
     parent::alterBuild($build, $entity, $display, $view_mode, $langcode);
-    $build['#attached']['css'][] = drupal_get_path('module', 'taxonomy') . '/taxonomy.css';
+    $build['#attached']['css'][] = drupal_get_path('module', 'taxonomy') . '/css/taxonomy.module.css';
     $build['#contextual_links']['taxonomy'] = array('taxonomy/term', array($entity->id()));
   }
 
diff --git a/core/modules/taxonomy/taxonomy.module b/core/modules/taxonomy/taxonomy.module
index 910b793..abe4970 100644
--- a/core/modules/taxonomy/taxonomy.module
+++ b/core/modules/taxonomy/taxonomy.module
@@ -1304,7 +1304,7 @@ function taxonomy_library_info() {
       drupal_get_path('module', 'taxonomy') . '/taxonomy.js' => array(),
     ),
     'css' => array(
-      drupal_get_path('module', 'taxonomy') . '/taxonomy.css' => array(),
+      drupal_get_path('module', 'taxonomy') . '/css/taxonomy.module.css' => array(),
     ),
     'dependencies' => array(
       array('system', 'jquery'),
diff --git a/core/modules/tour/css/tour-rtl.css b/core/modules/tour/css/tour.module-rtl.css
similarity index 100%
rename from core/modules/tour/css/tour-rtl.css
rename to core/modules/tour/css/tour.module-rtl.css
diff --git a/core/modules/tour/css/tour.css b/core/modules/tour/css/tour.module.css
similarity index 100%
rename from core/modules/tour/css/tour.css
rename to core/modules/tour/css/tour.module.css
diff --git a/core/modules/tour/tour.module b/core/modules/tour/tour.module
index fe9bc1a..8d96cfd 100644
--- a/core/modules/tour/tour.module
+++ b/core/modules/tour/tour.module
@@ -45,7 +45,7 @@ function tour_library_info() {
     'title' => 'Tour',
     'version' => VERSION,
     'css' => array(
-      $path . '/css/tour.css' => array('media' => 'screen'),
+      $path . '/css/tour.module.css' => array('media' => 'screen'),
     )
   );
 
diff --git a/core/modules/update/update-rtl.css b/core/modules/update/css/update.module-rtl.css
similarity index 100%
rename from core/modules/update/update-rtl.css
rename to core/modules/update/css/update.module-rtl.css
diff --git a/core/modules/update/update.css b/core/modules/update/css/update.module.css
similarity index 100%
rename from core/modules/update/update.css
rename to core/modules/update/css/update.module.css
diff --git a/core/modules/update/update.manager.inc b/core/modules/update/update.manager.inc
index bc84058..3efa66e 100644
--- a/core/modules/update/update.manager.inc
+++ b/core/modules/update/update.manager.inc
@@ -77,7 +77,7 @@ function update_manager_update_form($form, $form_state = array(), $context) {
     return $form;
   }
 
-  $form['#attached']['css'][] = drupal_get_path('module', 'update') . '/update.css';
+  $form['#attached']['css'][] = drupal_get_path('module', 'update') . '/css/update.module.css';
 
   // This will be a nested array. The first key is the kind of project, which
   // can be either 'enabled', 'disabled', 'manual' (projects which require
diff --git a/core/modules/update/update.report.inc b/core/modules/update/update.report.inc
index 607b523..dce85e6 100644
--- a/core/modules/update/update.report.inc
+++ b/core/modules/update/update.report.inc
@@ -247,7 +247,7 @@ function theme_update_report($variables) {
       $output .= theme('table', array('header' => $header, 'rows' => $rows[$type_name], 'attributes' => array('class' => array('update'))));
     }
   }
-  drupal_add_css(drupal_get_path('module', 'update') . '/update.css');
+  drupal_add_css(drupal_get_path('module', 'update') . '/css/update.module.css');
   return $output;
 }
 
diff --git a/core/modules/user/user-rtl.css b/core/modules/user/css/user.module-rtl.css
similarity index 100%
rename from core/modules/user/user-rtl.css
rename to core/modules/user/css/user.module-rtl.css
diff --git a/core/modules/user/user.css b/core/modules/user/css/user.module.css
similarity index 93%
rename from core/modules/user/user.css
rename to core/modules/user/css/user.module.css
index 2c88121..4677e8e 100644
--- a/core/modules/user/user.css
+++ b/core/modules/user/css/user.module.css
@@ -94,9 +94,9 @@ div.password-suggestions ul {
  * Toolbar icon.
  */
 .icon-user:before {
-  background-image: url("images/icon-user.png");
+  background-image: url("../images/icon-user.png");
 }
 .icon-user:active:before,
 .icon-user.active:before {
-  background-image: url("images/icon-user-active.png");
+  background-image: url("../images/icon-user-active.png");
 }
diff --git a/core/modules/user/user.module b/core/modules/user/user.module
index dcec95a..203a309 100644
--- a/core/modules/user/user.module
+++ b/core/modules/user/user.module
@@ -122,7 +122,7 @@ function user_theme() {
  */
 function user_page_build(&$page) {
   $path = drupal_get_path('module', 'user');
-  $page['#attached']['css'][$path . '/user.css'] = array('every_page' => TRUE);
+  $page['#attached']['css'][$path . '/css/user.module.css'] = array('every_page' => TRUE);
 }
 
 /**
@@ -2776,7 +2776,7 @@ function user_library_info() {
       drupal_get_path('module', 'user') . '/user.js' => array(),
     ),
     'css' => array(
-      drupal_get_path('module', 'user') . '/user.css' => array(),
+      drupal_get_path('module', 'user') . '/css/user.module.css' => array(),
     ),
     'dependencies' => array(
       array('system', 'jquery'),