diff --git a/script/minify.js b/script/minify.js
index bbf5aa0b23..8b79aaefc4 100755
--- a/script/minify.js
+++ b/script/minify.js
@@ -12,6 +12,7 @@ var minifiedHtml = minify.minify(html, {
   removeScriptTypeAttributes: true,
   removeStyleLinkTypeAttributes: true,
   minifyJS: true,
+  minifyCSS: true,
 });
 
 fs.writeFileSync('build/frontend.html', minifiedHtml);