diff --git a/ghost/admin/ember-cli-build.js b/ghost/admin/ember-cli-build.js
index e98fa1e7e6..622d90291b 100644
--- a/ghost/admin/ember-cli-build.js
+++ b/ghost/admin/ember-cli-build.js
@@ -145,6 +145,10 @@ module.exports = function (defaults) {
                 }
             }
         },
+        minifyCSS: {
+            // postcss already handles minification and this was stripping required CSS
+            enabled: false
+        },
         nodeAssets: {
             codemirror: codemirrorAssets(),
             simplemde: simplemdeAssets()