In material design has several special shadow classes to display containers as paper-like cards with shadow, everything should have a certain z-depth. These shadows make texts and images more appealing.
You can easily apply this shadow effect by adding a classes are
z-depth-0, z-depth-1, z-depth-2, z-depth-3, z-depth-4 and
z-depth-5 to an HTML tag. Finally
z-depth-0 can be used to remove shadows from elements that have z-depths by default.
Example :
<div class="row">
<div class="col s6 m4 l2">
<div class="amber box-demo z-depth-3">
<p>z-depth-3</p>
</div>
</div>
</div>
