diff --git a/core/css.js b/core/css.js
index 32f47a6f0..bac0d628c 100644
--- a/core/css.js
+++ b/core/css.js
@@ -84,9 +84,10 @@ Blockly.Css.inject = function(hasCss, pathToMedia) {
   // Strip off any trailing slash (either Unix or Windows).
   Blockly.Css.mediaPath_ = pathToMedia.replace(/[\\\/]$/, '');
   text = text.replace(/<<<PATH>>>/g, Blockly.Css.mediaPath_);
-  // Inject CSS tag.
+  // Inject CSS tag at start of head.
   var cssNode = document.createElement('style');
-  document.head.appendChild(cssNode);
+  document.head.insertBefore(cssNode, document.head.firstChild);
+
   var cssTextNode = document.createTextNode(text);
   cssNode.appendChild(cssTextNode);
   Blockly.Css.styleSheet_ = cssNode.sheet;