Overhanging form

I've created a page that is password protected on a page that I have set up to fit the width of both content and sidebar (sidebar has been removed) and the password form is cutting off on the right. I can't seem to find what I need to change in the CSS so that it fits the content area properly.

http://portfolio.staceymercer.co.uk/portfolio/cv/

The form works, it's just a bit unsightly and I'd like to resolve it. I'm guessing this is the CSS that needs to be changed but I can't find anything anyway in the terms of what I should be adding so that the form fits, obviously I only want it like this for this one page and not all forms

form, form[class] {
margin: 1.5em 0;
padding: 10px 20px;
border: 1px solid #ddd;
border-radius: 5px;
background: #f4f4f4;