LayoutTests/fast/css/container-query-listbox.html

<style>
#select {
    width: 100px;
    container-type: inline-size;
}

#option {
    color: red;
}

@container (min-width: 200px) {
    #option {
        color: blue;
    }
}
</style>
<p>Test passes if there is the second option is blue.</p>
<select multiple id="select">
    <option>A</option>
    <option id="option">B</option>
    <option>C</option>
    <option>D</option>
</select>
<script>

if (window.testRunner)
    testRunner.waitUntilDone();

requestAnimationFrame(() => {
    select.style.width = "300px";
    if (window.testRunner)
        testRunner.notifyDone();
});

</script>