<style>
#myShadowHost:hover {
    background: green;
}
#myShadowHost {
    position: absolute;
    width: 100px;
    height: 100px;
}
</style>
<body><div id="myShadowHost"><template shadowrootmode="open"><div>hover me</div></template></div></body>
<script src="../include.js"></script>
<script>
    test(() => {
        if (window.internals && window.internals.movePointerTo)
            internals.movePointerTo(50, 50);

        let s = getComputedStyle(myShadowHost);
        println("hovered bg: " + s.backgro