A CodePen by Shreyas R.

index.html

<div class="timer">
    <div class="timer">
        <div class="timer">
            <div class="timer">
                <div class="timer">
                    
                </div>
            </div>
        </div>
    </div>
</div>

style.css

body{
  text-align:center;
  overflow:hidden;
}

.timer {
    border-top: 5px solid #FF9000;
    border-left: 5px solid #A101A6;
    border-right: 5px solid #CFF700;
    border-bottom: 5px solid #0A64A4;
    display: inline-block;
    border-radius: 100%;
    padding: 6px;
    -webkit-animation: spin 5s linear infinite;
    line-height: 0px;
}
@-webkit-keyframes spin {
    0% {
        -webkit-transform: rotate(0deg);
    }
    100% {
        -webkit-transform: rotate(360deg);
    }
}