diff --git a/assets/ublock/mirror-candidates.txt b/assets/ublock/mirror-candidates.txt
index 642551260..91104b5c8 100644
--- a/assets/ublock/mirror-candidates.txt
+++ b/assets/ublock/mirror-candidates.txt
@@ -14,7 +14,10 @@ cdn.jsdelivr.net
 cdnjs.cloudflare.com
     ^cdnjs\.cloudflare\.com\/ajax\/libs\/
 code.jquery.com
-    ^code\.jquery\.com
+    # https://github.com/gorhill/uBlock/issues/357
+    # Avoid CSS-based themes, because relative URLs won't work from
+    # within a data: URI
+    ^code\.jquery\.com\/(?!.*\/themes\/.*\.css$)
 maxcdn.bootstrapcdn.com
     ^maxcdn\.bootstrapcdn\.com\/font-awesome\/
 netdna.bootstrapcdn.com