diff --git a/packages/www/rollup.config.js b/packages/www/rollup.config.js
index 88bc4db45..8285d1af8 100644
--- a/packages/www/rollup.config.js
+++ b/packages/www/rollup.config.js
@@ -15,6 +15,7 @@ const { processor, preprocess } = require("@modular-css/svelte")({
     after : [
         require("postcss-color-function")(),
         require("postcss-import")(),
+        require("postcss-calc")(),
     ],
 
     done : [