diff --git a/package.json b/package.json
index 38d64dd79..62970b1fd 100644
--- a/package.json
+++ b/package.json
@@ -4,7 +4,7 @@
   "private": true,
   "dependencies": {
     "@codemirror/commands": "^6.1.1",
-    "@codemirror/lang-css": "^6.0.0",
+    "@codemirror/lang-css": "^6.3.1",
     "@codemirror/lang-html": "^6.1.2",
     "@codemirror/lang-javascript": "^6.2.1",
     "@codemirror/lang-python": "6.1.2",
diff --git a/yarn.lock b/yarn.lock
index 365fff5ca..155a042cc 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -605,6 +605,19 @@ __metadata:
   languageName: node
   linkType: hard
 
+"@codemirror/lang-css@npm:^6.3.1":
+  version: 6.3.1
+  resolution: "@codemirror/lang-css@npm:6.3.1"
+  dependencies:
+    "@codemirror/autocomplete": "npm:^6.0.0"
+    "@codemirror/language": "npm:^6.0.0"
+    "@codemirror/state": "npm:^6.0.0"
+    "@lezer/common": "npm:^1.0.2"
+    "@lezer/css": "npm:^1.1.7"
+  checksum: 10/709994b0a787fe06ebac7a47c6a6a92c9680fe2b4479bbe2a72b27ad4d863953ad64a61b36f15098d00bd9a655bc9b3a3ecf2877354351ff873a01186fb38386
+  languageName: node
+  linkType: hard
+
 "@codemirror/lang-html@npm:^6.1.2":
   version: 6.4.9
   resolution: "@codemirror/lang-html@npm:6.4.9"
@@ -2561,7 +2574,7 @@ __metadata:
   resolution: "@raspberrypifoundation/editor-ui@workspace:."
   dependencies:
     "@codemirror/commands": "npm:^6.1.1"
-    "@codemirror/lang-css": "npm:^6.0.0"
+    "@codemirror/lang-css": "npm:^6.3.1"
     "@codemirror/lang-html": "npm:^6.1.2"
     "@codemirror/lang-javascript": "npm:^6.2.1"
     "@codemirror/lang-python": "npm:6.1.2"