Is it possible to do multi coloured borders? (Eg yellow inside red)

Answer 1

.multi {
width: 200px;
border: 3px solid red;
outline: 3px solid yellow;
}

<div class="multi">
</div>

Answer 2

Create a <div class="yellow> inside a <div class="red"> and In the css give the required height width and border to both the classes.