If you need to adjust the position of the navigation bar and the content box you can do that by changing the top values in the last two styles. If you make the top larger on the #page-wrap it will move the content box and navigation bar further down the page. If you make the top smaller (more negative) on the #page-wrap #nav-bar it will increase the distance between the navigation bar and the content.
Any chance you could let me see what’s happening on your slideshow page? On my end, it’s not affecting the home page, staff, podcast, image or gallery formats. There could be something else affecting it.