You can use the border and box-shadow properties along with CSS pseudo elements to achieve a triple-border sort of effect. See the example below for an idea of how to create three borders at the bottom of a div:
.triple-border:after {_x000D_
content: " ";_x000D_
display: block;_x000D_
width: 100%;_x000D_
background: #FFE962;_x000D_
height: 9px;_x000D_
padding-bottom: 8px;_x000D_
border-bottom: 9px solid #A3C662;_x000D_
box-shadow: -2px 11px 0 -1px #34b6af;_x000D_
}
_x000D_
<div class="triple-border">Triple border bottom with multiple colours</div>
_x000D_
You'll have to play around with the values to get the alignment correct. However, you can also achieve more flexibility, e.g. 4 borders if you put some of the attributes in the proper element rather than the pseudo selector.