<!DOCTYPE html>
<html>
<body>
    <div style="color: green">
        <div id="undefined-parent" style="color: red; -webkit-text-fill-color: inherit">Green</div>
    </div>
    <div style="color: purple; -webkit-text-fill-color: green">
        <div id="defined-parent" style="color: red; -webkit-text-fill-color: inherit">Green</div>
    </div>
</body>
<html>