<!DOCTYPE html>
<style>
div::first-line { color: green }
</style>
<body style="width: 100px" onload="document.body.style.width = 'auto'">
<div>
<span style="display: ruby-base-container">Some</span>
<span style="display: ruby-base-container">text that is fairly long</span>
</div>
</body>