CSS Div with Overflow in a Variable Width Container

I am try开发者_如何学运维ing to display code on my site, but the container it is in is 90%, and thus when the code is more that the page can fit, it extends off the the right. I wanted to have it overflow inside a div very much like github.

Thank you :)

Can you do this?

<div style="width:90%; border: solid 1px red;"> //Outer (current div)
  <div style="overflow: auto;"> //width: auto; (default)
    <div style="width: 4000px;">Test Wide Content ...</div> //content!
  </div>
</div>