diff --git a/src/optimize/postcss.config.js b/src/optimize/postcss.config.js
index 0eb33b6a67a76..b08cd293c146c 100644
--- a/src/optimize/postcss.config.js
+++ b/src/optimize/postcss.config.js
@@ -3,7 +3,8 @@ module.exports = {
     require('autoprefixer')({
       browsers: [
         'last 2 versions',
-        '> 5%'
+        '> 5%',
+        'Safari 7' // for PhantomJS support
       ]
     })
   ]