diff --git a/purgecss.config.js b/purgecss.config.js
index 1090227e..4667dd1e 100644
--- a/purgecss.config.js
+++ b/purgecss.config.js
@@ -4,5 +4,6 @@ module.exports = {
   defaultExtractor: content => content.match(/[\w-/:]+(?<!:)/g) || [],
   paths: () => glob.sync([
     'source/**/*.{md,twig}'
-  ])
+  ]),
+  whitelistPatterns: [/hljs/, /language/]
 }