Apply a slight shadow when container is scrolled
This little effect is part of the all the little details that make your page more pleasant and intutitive for your users.
The goal is to add a slight shadow at the top of the scrolled container, but only when the container has been scrolled to the bottom. It hints the user that more content has scrolled underneath.
Here is a demo:
See the Pen Top-shadow on scrolled container by Sébastien Roch (@sebastien-roch) on CodePen.
There are also pure CSS version of this effect like the one from the great Lea Verou (http://lea.verou.me/2012/04/background-attachment-local/), but the CSS is slightly more complicated!