Wanting to use a background image for my app !

I put in my layout layout file the following declaration just before the closing head tag ( .. </head> )

 

<style type="text/css">
    body{
    background-image:url('images/pattern.png');
    font-family: 'Ubuntu', arial, sans-serif;
    }
</style>

 

For some reason ..... it is not showing up ... I even tried to put it directly the css file ... it still does not show up as background.

I also tried writing it like this : background-image: URL('static','images/pattern.png'); it still does not work !

the "pattern.png" is well inside the images folder in the static folder of my app !

Can someone please tell me ... how come it is not working .. and how can I make my background image showing up as background image ( repeat xy should be considered by default  so it was not specified ...) even when it is specified .. nothing shows up !

 

Please help .. please assist ...

 

I am sure this should be simple ! .. but it is not working !