TwentyEleven: How to reduce whitespace below menu and Page Title

I’m a WordPress newbie and am trying to reduce the empty white space below the twentyeleven menu and the Page title and other content.
Here is the space I’m trying to describe.

Here’s the site I’m beginning to create.

A few things I’ve already modified in my twenty eleven child theme include:

• Removing the default twenty eleven header images and uploading and using a custom header image in place of the Site title text.
  I did this by modifying child theme file functions.php using these techniques.
• Resizing the header image using the Resize Twenty Eleven Header plugin.

I have searched all the forum posts on www.ads-software.com and tried several of the techniques to add css to the style.css file in my 2011 child theme but I am unable to reduce the vertical white space.

Any suggestions or help would be much appreciated. Thanks for your consideration.