index.html

<!DOCTYPE html>
<html>
    <head>
    	<link href="https://fonts.googleapis.com/css?family=Quicksand:400,700" rel="stylesheet">
    	<meta name="viewport" content="width=device-width, initial-scale=1.0">
    	<title>Pride</title>
    </head>

    <body>
        <style>
        	body {
        		font-family: 'Quicksand';
        		font-weight: 700;
        		font-size: 24px;
        		background-color: #333;
        	}
	
        	.container {
        		width: 300px;
        		text-align: center;
        		margin: 0 auto;
        		margin-top: 100px;
        	}
        </style>

        <div class = "container">
        	<div class = "rainbow">
        		Celebrate<br><span style = "font-size: 36px">PRIDE</span>
        		<br>2019
        	</div>
        </div>
    </body>
</html>

<script src = "js/rainbow.js"></script>