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<html>
<head>
<style>
body {
    font-family: Ahem;
    font-size: 16px;
    -webkit-font-smoothing: none;
    color: rgba(0, 0, 0, 0.1);
}
</style>
</head>
<body>
<!-- All texts inside the ruby should be highlighted. -->
a<ruby>1<rt>1</rt>2<rt>2</rt>3<rt>3</rt>4<rt>4</rt></ruby>b
<script>
var range = document.createRange();
range.selectNodeContents(document.body);
window.getSelection().addRange(range);
</script>
</body>
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