diff --git a/django/contrib/admin/media/css/base.css b/django/contrib/admin/media/css/base.css
index 88f7d9a95a..9760d67dc4 100644
--- a/django/contrib/admin/media/css/base.css
+++ b/django/contrib/admin/media/css/base.css
@@ -4,11 +4,11 @@
 */
 
 /* Block IE 5 */
-@import "null?\"\{";
+@import "null.css?\"\{";
 
 /* Import other styles */
 @import url('global.css');
 @import url('layout.css');
 
 /* Import patch for IE 6 Windows */
-/*\*/ @import "patch-iewin.css"; /**/
\ No newline at end of file
+/*\*/ @import "patch-iewin.css"; /**/