It can be styled in the same way as any other element.
It will be an <input> tag. To specify just that <input> tag you need its ID or a class, or the ID of a containing element.
Start with:
Code:
#searchContent input{background-color:red;}
You'll discover that this alters the input box and the button ( they are both <input>) To separate them out you are going to need to either 1. play around with the first-child selector in the css but this is buggy across browsers in my opinion. 2. Edit the code to add a ID or a class to one or both elements.
Or you could try this:
Code:
#searchContent input[type=text]{background-color:red;}
But I think this is buggy across browsers too so I would really recommend adding IDs or classes to the elements.