Styling - No Room Available (div)

Hi there,
Before I ask, I'll just say that I'm pleased with Solidres so far.
My problem is with styling, I've decided to style span and div that handles "No room available" text.
I can't find it anywhere in php files and I need exact location so I can add 1 more div to it and style it as I please in custom.css file.
As I can see:
<div class="span3">
<div class="inner"> No room available</div>
</div>
but I cant style those without adding a new span or div to handle "no room available". Please tell me the location of the file and line, I can handle the rest. Thanks

I've attached a photo!