How to achieve this design?

Hi,

I'm trying to do something like what appears in this page: http://shun.kaiusaltd.com.

At the top, when you scroll the top part gets covered by that bottom part.

I know how to achieve this by using position: fixed;, but this comes with the inconvenience of being unable to use links and in general I dislike using fixed elements.

So, any ideas how this guys made it? I tried looking at their Page Source, but couldn't find anything.

Thanks for any help.