Firefox CSS problem

Hi all,

I’m modifying the Thirteen template but I’m getting some weird problems with the sidebar in Firefox. All the other browsers (IE, Opera and Safari) are displaying it fine. The background image in the Navigation title isn’t showing up and the Search form is pushed to the top.

Here’s the site https://www.waitinginthefield.com

My css is at https://www.waitinginthefield.com/wp-content/themes/thirteen/style.css

Thanks!