<div class="tooltip">I'm a tooltip.</div>
.tooltip {
	position: relative;
	display: inline-block;
	padding: 5px 10px;
	background: #80D4C8;
}
.tooltip:before {
	content: "";
	display: block;
	position: absolute;
    left: 50%;
    margin-left: -5px;
    bottom: -5px;
    width: 0; 
    height: 0; 
    border-left: 5px solid transparent;
    border-right: 5px solid transparent;
    border-top: 5px solid #80D4C8;
}

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