diff --git a/classes/local/controllers/maintenance_static_page.php b/classes/local/controllers/maintenance_static_page.php
index 55ae182..74f3a33 100644
--- a/classes/local/controllers/maintenance_static_page.php
+++ b/classes/local/controllers/maintenance_static_page.php
@@ -291,12 +291,12 @@ class maintenance_static_page {
             if (($rel != 'stylesheet') || ($href == '')) {
                 continue;
             }
-            $filename = $this->save_url_file($href);
-            if (is_null($filename)) {
+            $saved = $this->save_url_file($href);
+            if (is_null($saved['url'])) {
                 $url = $href; // Skipped, use original URL.
             } else {
-                $this->update_link_stylesheet_parse($filename);
-                $url = $this->get_url_for_file($filename);
+                $this->update_link_stylesheet_parse($saved['file'], dirname($href));
+                $url = $this->get_url_for_file($saved['url']);
             }
             $link->setAttribute('href', $url);
         }
@@ -306,7 +306,31 @@ class maintenance_static_page {
      * Checks for urls inside filename.
      * @param string $filename
      */
-    private function update_link_stylesheet_parse($filename) {
+    private function update_link_stylesheet_parse($filename, $baseref) {
+        global $CFG;
+
+        $contents = file_get_contents($filename);
+        if (!preg_match_all('#url\([\'"]?([^\'"\)]+)#', $contents, $matches)) {
+            return;
+        }
+        foreach ($matches[1] as $original_url) {
+            // Allow incomplete URLs in CSS, assume it is from moodle root.
+            if (self::is_url($original_url)) {
+                $full_url = $original_url;
+            } else if ($original_url[0] == '/') {
+                $full_url = $CFG->wwwroot.$original_url;
+            } else {
+                $full_url = $baseref.'/'.$original_url;
+            }
+
+            $saved = $this->save_url_file($full_url);
+            if (!is_null($saved)) {
+                $final_url = $this->get_url_for_file($saved['url']);
+                $contents = str_replace($original_url, $final_url, $contents);
+            }
+        }
+
+        file_put_contents($filename, $contents);
     }
 
     /**
@@ -346,11 +370,11 @@ class maintenance_static_page {
      * @return string Output URL.
      */
     private function generate_file_url($url) {
-        $filename = $this->save_url_file($url);
-        if (is_null($filename)) {
+        $saved = $this->save_url_file($url);
+        if (is_null($saved)) {
             return $url; // Skipped, use original URL.
         }
-        return $this->get_url_for_file($filename);
+        return $this->get_url_for_file($saved['url']);
     }
 
     /**
@@ -387,13 +411,14 @@ class maintenance_static_page {
         $data = self::file_get_data($url);
 
         $mime = trim(base64_encode($data['mime']), '=');
-        $filename = sha1($data['contents']).'.'.$mime;
-        $filepath = $this->get_resources_folder().'/'.$filename;
+        $url = sha1($data['contents']).'.'.$mime;
+        $filepath = $this->get_resources_folder().'/'.$url;
         file_put_contents($filepath, $data['contents']);
 
         if ($this->preview) {
-            $filename = 'preview/'.$filename;
+            $url = 'preview/'.$url;
         }
-        return $filename;
+
+        return ['file' => $filepath, 'url' => $url];
     }
 }
diff --git a/tests/phpunit/local/controllers/fixtures/subdir/withurls-subdir.css b/tests/phpunit/local/controllers/fixtures/subdir/withurls-subdir.css
new file mode 100644
index 0000000..3e9c1a8
--- /dev/null
+++ b/tests/phpunit/local/controllers/fixtures/subdir/withurls-subdir.css
@@ -0,0 +1 @@
+@import url(../simple.css);
diff --git a/tests/phpunit/local/controllers/fixtures/withurls-quoted.css b/tests/phpunit/local/controllers/fixtures/withurls-quoted.css
new file mode 100644
index 0000000..012773c
--- /dev/null
+++ b/tests/phpunit/local/controllers/fixtures/withurls-quoted.css
@@ -0,0 +1,7 @@
+a {
+    font-size: 200%;
+}
+
+div {
+    background-image: url('/auth/outage/tests/phpunit/local/controllers/fixtures/catalyst.png');
+}
\ No newline at end of file
diff --git a/tests/phpunit/local/controllers/fixtures/withurls.css b/tests/phpunit/local/controllers/fixtures/withurls.css
new file mode 100644
index 0000000..7e1e985
--- /dev/null
+++ b/tests/phpunit/local/controllers/fixtures/withurls.css
@@ -0,0 +1,7 @@
+a {
+    font-size: 200%;
+}
+
+div {
+    background-image: url(/auth/outage/tests/phpunit/local/controllers/fixtures/catalyst.png);
+}
\ No newline at end of file
diff --git a/tests/phpunit/local/controllers/maintenance_static_page_test.php b/tests/phpunit/local/controllers/maintenance_static_page_test.php
index 61255c8..61d422d 100644
--- a/tests/phpunit/local/controllers/maintenance_static_page_test.php
+++ b/tests/phpunit/local/controllers/maintenance_static_page_test.php
@@ -87,6 +87,51 @@ class maintenance_static_page_test extends auth_outage_base_testcase {
         self::assertContains($external_css_link, $generated);
     }
 
+    public function test_updatelinkstylesheet_urls() {
+        $local_css_link = $this->get_fixture_path('withurls.css');
+        $html = "<!DOCTYPE html>\n".
+                '<html><head><link href="'.$local_css_link.'" rel="stylesheet" /><title>Title</title></head>'.
+                '<body>Content</body></html>';
+        $page = maintenance_static_page::create_from_html($html);
+        $page->generate();
+
+        // Check for css file.
+        self::assertFileExists($page->get_resources_folder().'/622ef6e83acfcb274cdf37bdb3bffa0923f9a7ad.dGV4dC9wbGFpbg');
+
+        // Check for catalyst.png file referenced in url(..) of css.
+        self::assertFileExists($page->get_resources_folder().'/ff7f7f87a26a908fc72930eaefb6b57306361d16.aW1hZ2UvcG5n');
+    }
+
+    public function test_updatelinkstylesheet_urls_quoted() {
+        $local_css_link = $this->get_fixture_path('withurls-quoted.css');
+        $html = "<!DOCTYPE html>\n".
+                '<html><head><link href="'.$local_css_link.'" rel="stylesheet" /><title>Title</title></head>'.
+                '<body>Content</body></html>';
+        $page = maintenance_static_page::create_from_html($html);
+        $page->generate();
+
+        // Check for css file.
+        self::assertFileExists($page->get_resources_folder().'/1d84b6d321fef780237f84834b7316c079221a31.dGV4dC9wbGFpbg');
+
+        // Check for catalyst.png file referenced in url(..) of css.
+        self::assertFileExists($page->get_resources_folder().'/ff7f7f87a26a908fc72930eaefb6b57306361d16.aW1hZ2UvcG5n');
+    }
+
+    public function test_updatelinkstylesheet_urls_subdir() {
+        $local_css_link = $this->get_fixture_path('subdir/withurls-subdir.css');
+        $html = "<!DOCTYPE html>\n".
+                '<html><head><link href="'.$local_css_link.'" rel="stylesheet" /><title>Title</title></head>'.
+                '<body>Content</body></html>';
+        $page = maintenance_static_page::create_from_html($html);
+        $page->generate();
+
+        // Check for css file.
+        self::assertFileExists($page->get_resources_folder().'/4ea71b83ab326a15d0d784b34fcda702b6a7427d.dGV4dC9wbGFpbg');
+
+        // Check for file referenced in url(..) of css.
+        self::assertFileExists($page->get_resources_folder().'/a02a8a442fa82d5205ffb24722d9df7f35161f56.dGV4dC9wbGFpbg');
+    }
+
     public function test_updateimages() {
         $local_img_link = $this->get_fixture_path('catalyst.png');
         $external_img_link = 'http://google.com/coolstyle.css';
@@ -167,9 +212,7 @@ class maintenance_static_page_test extends auth_outage_base_testcase {
                 '<html><head><title>Title</title></head>'.
                 '<body>Content<img src="'.$link.'" /></body></html>';
         $page = maintenance_static_page::create_from_html($html);
-        $page->set_preview(true);
         $page->generate();
-        $generated = trim(file_get_contents($page->get_template_file()));
 
         // This checks if content is correct and mime type is correct from the encoded name.
         $file = $page->get_resources_folder().'/ff7f7f87a26a908fc72930eaefb6b57306361d16.aW1hZ2UvcG5n';