update: Change cards design and write documentation

docs/index.md

@@ -1 +1,16 @@
-## Documentation
+## Documentation
+
+This theme use LESS to override current CSS. All files and assets are in the "stylesheets" folder at the root of the theme.
+To make it more readable, all differents parts are splitted in the "component" folder.
+
+If you want to contribute, please download the folder and continue in this direction using small and maintainable components. 
+
+Consider this is my first Matomo theme, be compliant and please tell me how to make it better if you see any errors.
+
+### Overrided componants
+- Page card style
+- Dashboard widgets
+- Header
+- Site menu
+- Search bar
+- Sparkline (thank to https://lw1.at for showing the right way)