<!DOCTYPE html>
<html>
<head>

<svg xmlns="http://www.w3.org/2000/svg">
<defs>
<font id="HelveticaLight" horiz-adv-x="1024">
<font-face units-per-em="2048" ascent="1577" descent="-471" font-family="Helvetica"/>
<glyph unicode="l" horiz-adv-x="455" d="M137 1469H317V0H137z"/>
</font>
</defs>
</svg>

<style>
@font-face {
    font-family: "WebFont1";
    src: url("Helvetica_light.svg") format("svg");
}
@font-face {
    font-family: "WebFont2";
    src: url("#HelveticaLight");
}
</style>

</head>
<body>
<div style="font-size: 48px;">
<div style="font-family: 'WebFont1';"><span id="target1">lll</span></div>
<div style="font-family: 'WebFont2';"><span id="target2">lll</span></div>
<div><span id="reference">lll</span></div>
</div>
</body>
</html>