diff --git a/build/postcss.config.js b/build/postcss.config.js
index 157291ffd2e2a77e2ff31f64b547cb5d83b2c95c..e85abfa04f6dbf9b7cea160cab255ff3a82814bf 100644
--- a/build/postcss.config.js
+++ b/build/postcss.config.js
@@ -9,6 +9,7 @@ module.exports = (ctx) => ({
   plugins: {
     autoprefixer: {
       cascade: false
-    }
+    },
+    'postcss-calc': {}
   }
 })
diff --git a/package.json b/package.json
index 994e8a8b65f13b16f4e1cb61e8f680925b4a4e04..b6b6bb74cd1be28968533c3e56501a31c6d57491 100644
--- a/package.json
+++ b/package.json
@@ -114,6 +114,7 @@
     "nodemon": "^1.17.3",
     "npm-run-all": "^4.1.2",
     "popper.js": "^1.14.3",
+    "postcss-calc": "^6.0.1",
     "postcss-cli": "^5.0.0",
     "qunitjs": "^2.4.1",
     "rollup": "^0.58.0",