diff --git a/flash.css b/flash.css
index 7c9f5e8..afb204c 100644
--- a/flash.css
+++ b/flash.css
@@ -87,6 +87,9 @@
 select:after {
   background-image: -webkit-repeating-linear-gradient(135deg, #000, #000 1px, transparent 2px, transparent 5px);
   background-image: repeating-linear-gradient(-45deg, #000, #000 1px, transparent 2px, transparent 5px);
+  background-size: 8px 12px;
+  -webkit-backface-visibility: hidden;
+  backface-visibility: hidden;
 }
 
 #answer, button {