Issues with masthead or hgroup-wrap not resizing properly

This is the web site that I am currently creating using the Catch Everest theme http://carlwoodall.com/wordpress I have created a Child Theme (I know you mentioned previously that I didn't need to have a Child Theme, however I am more comfortable working with the theme that way). In the Child Theme I have customized the masthead area. When viewing the site on the internet, full view, the Masthead looks perfect. The issue I am having is that the when I reduce the screen size on my monitor and/or look at it on my iPad, there is a white gap that shows up above the menu. When I use Firebug to look at the area, I see that the Masthead and the hgroup-wrap are not reducing in height when resized. Not sure what I should do to get rid of the white gap. Thank you, again, for your assistance.