diff --git a/source/installation/installation.rst b/source/installation/installation.rst
index 4116262ed..53f245fb6 100644
--- a/source/installation/installation.rst
+++ b/source/installation/installation.rst
@@ -205,6 +205,24 @@ The main bundle require two scripts to be executed :
 
 Those will populate database, respectively, with countries (using ISO declaration) and languages (using, also, ISO informations).
 
+
+Building CSS (optionnal)
+^^^^^^^^^^^^^^^^^^^^^^^^
+
+For this step, npm must be installed.
+
+A build version of the needed CSS file is provided within the main bundle `Resources/public/css/chillmain.css`. For rebuilding it :
+
+
+.. code-block:: bash
+
+   #in the main bundle directory ( vendor/chill-project/main/ )
+   cd Resources/
+   npm install
+   grunt
+
+
+
 Launch your server
 ^^^^^^^^^^^^^^^^^^