<!DOCTYPE html>
<html>
<body>
<!-- overline color of "inside" should be blue -->
<div style="color: green; text-decoration: line-through; font-family: Ahem; line-height: 1.2em">
    line-through only
    <div style="color: red; text-decoration: overline;">
        outside
        <div style="color: blue; text-decoration: overline;">
            inside
        </div>
    </div>
</div>
</body>
</html>