<html>
<head>
<style>
/* explicitly load a font that supports the "fi" ligature */
@font-face {
  font-family: test;
  src: url(../fonts/mplus/mplus-1p-regular.ttf);
}
body {
  font-family: test, serif;
  padding: 20px;
}
</style>
</head>

<body>
<div id="div" style="font-size: 40px">ifi</div>
</body>
</html>