diff --git a/README.md b/README.md
index 969fad5..de576d7 100644
--- a/README.md
+++ b/README.md
@@ -10,9 +10,18 @@
 This addon combines your `vendor.js` and `<your-app-name>.js` into a single
 file called `app.js`.
 
+This addon combines your `css.js` and `<your-app-name>.css` into a single
+file called `app.css`.
+
 You also need to update your `app/index.html`:
 
 ```html
+<!-- change the following -->
+<link rel="stylesheet" href="{{rootURL}}assets/vendor.css">
+<link rel="stylesheet" href="{{rootURL}}assets/my-project.css">
+<!-- to -->
+<link rel="stylesheet" href="{{rootURL}}assets/app.css">
+
 <!-- change the following -->
 <script src="{{rootURL}}assets/vendor.js"></script>
 <script src="{{rootURL}}assets/my-project.js"></script>
diff --git a/index.js b/index.js
index fa1926c..1f65d57 100644
--- a/index.js
+++ b/index.js
@@ -12,12 +12,20 @@ module.exports = {
       return tree;
     }
 
-    return mergeTrees([tree, concat(tree, {
+    const jsTree = mergeTrees([tree, concat(tree, {
       headerFiles: [
         'assets/vendor.js',
         `assets/${this.project.pkg.name}.js`
       ],
       outputFile: 'assets/app.js'
     })]);
+
+    return mergeTrees([jsTree, concat(jsTree, {
+      headerFiles: [
+        'assets/vendor.css',
+        `assets/${this.project.pkg.name}.css`
+      ],
+      outputFile: 'assets/app.css'
+    })]);
   }
 };