diff --git a/core/lib/Drupal/Component/Utility/CSS.php b/core/lib/Drupal/Component/Utility/CSS.php
index 8bcd429..7ade38d 100644
--- a/core/lib/Drupal/Component/Utility/CSS.php
+++ b/core/lib/Drupal/Component/Utility/CSS.php
@@ -15,8 +15,9 @@ class CSS {
   /**
    * Prepares a string for use as a CSS identifier (element, class, or ID name).
    *
-   * http://www.w3.org/TR/CSS21/syndata.html#characters shows the syntax for valid
-   * CSS identifiers (including element names, classes, and IDs in selectors.)
+   * http://www.w3.org/TR/CSS21/syndata.html#characters
+   * The above URL shows the syntax for valid CSS identifiers
+   * (including element names, classes, and IDs in selectors.)
    *
    * @param $identifier
    *   The identifier to clean.