foo.diff

diff --git i/lib/models/addon.js w/lib/models/addon.js
index 2f9de9d00..1734e3604 100644
--- i/lib/models/addon.js
+++ w/lib/models/addon.js
@@ -298,6 +298,10 @@ let addonProto = {
       public: 'public',
     };
 
+    if (this.isModuleUnification()) {
+      this.treePaths.styles = 'src/ui/styles';
+    }
+
     this.treeForMethods = defaultsDeep({}, DEFAULT_TREE_FOR_METHODS);
 
     if (this.parent) {
@@ -360,7 +364,7 @@ let addonProto = {
      @return {Boolean} Whether this is using a module unification format.
   */
   isModuleUnification() {
-    return false;
+    return this.has('src');
   },
 
   /**
@@ -1424,6 +1428,18 @@ let addonProto = {
     }
   },
 
+  /**
+    Returns whether or not the given file name is present in this project.
+
+    @private
+    @method has
+    @param  {String}  file File name
+    @return {Boolean}      Whether or not the file is present
+   */
+  has(file) {
+    return fs.existsSync(path.join(this.root, file)) || fs.existsSync(path.join(this.root, `${file}.js`));
+  },
+
   /**
     Augments the applications configuration settings.