<!DOCTYPE html>
<html>
<head>
<title>Title of the document</title>
<style>
.line:after {
content: '\A';
white-space: pre;
}
</style>
</head>
<body>
<h3>
<span class="line">This is the first line</span>
<span class="secondary-label">second line</span>
</h3>
</body>
</html>