css/css-fonts/variations/variable-opsz-ref.html

<!DOCTYPE html>
<html class="reftest-wait">
<meta charset="utf-8">
<style>
    @font-face {
    font-family: variabletest_box;
    src: url(resources/variabletest_box.ttf);
    }

    body {
    font-family: variabletest_box, sans-serif;
    font-optical-sizing: none;
    }
</style>
<div style="font-size:   6px; font-variation-settings: 'opsz'    6;">B</div>
<div style="font-size:  12px; font-variation-settings: 'opsz'   12;">B</div>
<div style="font-size:  24px; font-variation-settings: 'opsz'   24;">B</div>
<div style="font-size:  48px; font-variation-settings: 'opsz'   48;">B</div>
<div style="font-size:  64px; font-variation-settings: 'opsz'   64;">B</div>
<div style="font-size: 128px; font-variation-settings: 'opsz'  128;">B</div>
<div style="font-size:  24px; font-variation-settings: 'opsz'  128;">B</div>
<div style="font-size:  48px; font-variation-settings: 'opsz'   12;">B</div>
<script>
    document.fonts.ready.then(
        () => { document.documentElement.classList.remove("reftest-wait"); });
</script>
</html>