diff --git a/package.json b/package.json
index 4a54b2a2d..40594327b 100644
--- a/package.json
+++ b/package.json
@@ -4,6 +4,7 @@
   "description": "",
   "main": "dist/bundle.js",
   "dependencies": {
+    "@ungap/custom-elements": "^1.3.0",
     "break_infinity.js": "^2.0.0",
     "clipboard": "^2.0.11",
     "eventemitter3": "^4.0.7",
diff --git a/src/Synergism.ts b/src/Synergism.ts
index 9d748e99c..595919e7b 100644
--- a/src/Synergism.ts
+++ b/src/Synergism.ts
@@ -1,3 +1,4 @@
+import '@ungap/custom-elements'
 import type { DecimalSource } from 'break_infinity.js'
 import Decimal from 'break_infinity.js'
 import LZString from 'lz-string'