diff --git includes/common.inc includes/common.inc
index a04e52d..21ae120 100644
--- includes/common.inc
+++ includes/common.inc
@@ -1925,7 +1925,7 @@ function drupal_build_css_cache($types, $filename) {
           $base = base_path() . dirname($file) .'/';
           _drupal_build_css_path(NULL, $base);
           // Prefix all paths within this CSS file, ignoring external and absolute paths.
-          $data .= preg_replace_callback('/url\([\'"]?(?![a-z]+:|\/+)([^\'")]+)[\'"]?\)/i', '_drupal_build_css_path', $contents);
+          $data .= preg_replace_callback('/url\s*\([\'"]?(?![a-z]+:|\/+)([^\'")]+)[\'"]?\)/i', '_drupal_build_css_path', $contents);
         }
       }
     }
@@ -2030,9 +2030,16 @@ function _drupal_load_stylesheet($matches) {
   $filename = $matches[1];
   // Load the imported stylesheet and replace @import commands in there as well.
   $file = drupal_load_stylesheet($filename);
-  // Alter all url() paths, but not external.
-  return preg_replace('/url\(([\'"]?)(?![a-z]+:)([^\'")]+)[\'"]?\)?;/i', 'url(\1'. dirname($filename) .'/', $file);
-}
+  // Determine the file's directory.
+  $directory = dirname($filename);
+  // If the file is in the current directory, make sure '.' doesn't appear in
+  // the url() path.
+  $directory = $directory == '.' ? '' : $directory .'/';
+
+  // Alter all internal url() paths. Leave external paths alone. We don't need
+  // to normalize absolute paths here (i.e. remove folder/... segments) because
+  // that will be done later.
+  return preg_replace('/url\s*\(([\'"]?)(?![a-z]+:|\/+)/i', 'url(\1'. $directory, $file);}
 
 /**
  * Delete all cached CSS files.