Framework Basics - Foundation - Background url problem

I'm using Foundation. Basically I'm following Framework basics to the letter. I'm up to styling the panel.

I'm using almost exactly the same markup as the instructor but for some reason when I'm trying to use a background image within a div it does not show at all. My markup is as follows:

```<div class="row headline">

<div class="large-9 columns">
    <div class="luisa left">

    </div>

</div> ```

(I do have the other 3 columns to add up 12 but I'm just pasting here what is not working)

Then in my css these are my styles:

.headline { margin-top: 80px; background: #EDDA06; margin-bottom: 25px; padding: 30px; }

.luisa { background: url(main-illustration.png) no-repeat; }

When I try to add the background url to the class luisa it doesn't show up. If I add it to headline it does. I really don't have a clue what's happening. It seems so simple yet even though I'm trying all sorts of things, this div will not accept any image as background.

Help! thank you.