diff --git a/edit/codemirror-default.js b/edit/codemirror-default.js
index 48f09102..9a6142f6 100644
--- a/edit/codemirror-default.js
+++ b/edit/codemirror-default.js
@@ -100,7 +100,13 @@
     });
   }
 
-  CodeMirror.mimeModes['text/css'].propertyKeywords['mix-blend-mode'] = true;
+  Object.assign(CodeMirror.mimeModes['text/css'].propertyKeywords, {
+    'mix-blend-mode': true,
+    'isolation': true,
+  });
+  Object.assign(CodeMirror.mimeModes['text/css'].valueKeywords, {
+    'isolate': true,
+  });
 
   const MODE = {
     stylus: 'stylus',