diff --git a/.github/lighthouse/lighthouserc-netlify-preview.json b/.github/lighthouse/lighthouserc-netlify-preview.json
index 481e9a54..26ed1c1c 100644
--- a/.github/lighthouse/lighthouserc-netlify-preview.json
+++ b/.github/lighthouse/lighthouserc-netlify-preview.json
@@ -8,7 +8,7 @@
       "assertions": {
         "first-contentful-paint": ["warn", { "minScore": 0.6 }],
         "font-display": "off",
-        "unused-css-rules": "off",
+        "unused-css-rules": "on",
         "uses-rel-preconnect": "off",
         "is-crawlable": "off"
       }