How to remove menu from frontpage

I would like the menu to only show after you scroll down the page, just as the demo shows. Please advise.
http://lindleylawoffice.com/lawzzz/

It does exactly as you like. Have you been able to fix it?

I figured it out. I updated the css file with the frontpage active script.

P,ease remember not to edit template core css files. Please use override.css instead as it is much easier with future template updates to replace only one file instead of bringing back all changes from different files.