diff --git a/site/decodal-site/src/lib/codemirror/decodal.js b/site/decodal-site/src/lib/codemirror/decodal.js
index ca81334..b07631d 100644
--- a/site/decodal-site/src/lib/codemirror/decodal.js
+++ b/site/decodal-site/src/lib/codemirror/decodal.js
@@ -1,4 +1,4 @@
-import { LRLanguage, LanguageSupport, HighlightStyle, syntaxHighlighting, foldNodeProp, foldInside, indentNodeProp } from '@codemirror/language';
+import { LRLanguage, LanguageSupport, HighlightStyle, syntaxHighlighting, foldNodeProp, indentNodeProp } from '@codemirror/language';
 import { styleTags, tags as t } from '@lezer/highlight';
 import { parser } from './decodal-parser.js';
 
@@ -25,13 +25,22 @@ const parserWithMetadata = parser.configure({
       LetExpression: context => context.column(context.node.from) + context.unit,
     }),
     foldNodeProp.add({
-      Object: foldInside,
-      Array: foldInside,
-      MatchExpression: foldInside,
+      Object: foldDelimited('lBrace', 'rBrace'),
+      Array: foldDelimited('lBracket', 'rBracket'),
+      MatchExpression: foldDelimited('lBrace', 'rBrace'),
     }),
   ],
 });
 
+function foldDelimited(openName, closeName) {
+  return (node) => {
+    const open = node.getChild(openName);
+    const close = node.getChild(closeName);
+    if (!open || !close || open.to >= close.from) return null;
+    return { from: open.to, to: close.from };
+  };
+}
+
 export const decodalLanguage = LRLanguage.define({
   parser: parserWithMetadata,
   languageData: {