I want my menu bar to go the full length of the page

My website: http://bookthatevent.com
I'd like the menu bar (actually the page names/words) to across the top of the page (be spread our evenly). Can you give me code to do that?

Thank you!

 

Hello,

Paste this code in Custom CSS
Appearance > Theme Option > Styling Option > Custom CSS

Code:

#menu .ddsmoothmenu li{
margin-right:75px;
} 

Thanks & Regards
Gourav Shrivastava