<!DOCTYPE html>
<html>
<head>
<script>
if (window.internals)
    internals.settings.setMinimumFontSize(32);
</script>
<style>
.test {
    display: inline-block;
    width: 100px;
    border: 2px solid black;
}
</style>
</head>
<body style="font-size: 32px;">
<div class="test" style="font-size: 16px; line-height: normal;">Hello World</div>
<div class="test" style="font-size: x-small; line-height: normal;">Hello World</div>
<div class="test" style="font-size: 16px; line-height: 24px;">Hello World</div>
<div class="test" style="font-size: x-small; line-height: 15px;">Hello World</div>
<div class="test" style="font-size: 16px; line-height: 150%;">Hello World</div>
<div class="test" style="font-size: x-small; line-height: 150%;">Hello World</div>
<div class="test" style="font-size: 16px; line-height: 1.5;">Hello World</div>
<div class="test" style="font-size: x-small; line-height: 1.5;">Hello World</div>
</body>
</html>