<!doctype html>
<title>CSS Container Queries Test: Canvas as dynamic size container for focusable child with display</title>
<link rel="help" href="https://drafts.csswg.org/css-conditional-5/#size-container">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="support/cq-testcommon.js"></script>
<style>
canvas {
display: block;
width: 100px;
height: 100px;
container-type: size;
}
#target { display: none; }
@container (width = 200px) {
#target { display: block; }
}
</style>
<p>Test passes if there is a filled green square.</p>
<canvas id="canvas">
<div id="target" tabIndex="1"></div>
</canvas>
<script>
setup(() => assert_implements_container_queries());
test(() => {
target.focus();
assert_not_equals(document.activeElement, target);
}, "Initially display:none, not focusable");
test(() => {
canvas.style.width = "200px";
target.focus();
assert_equals(document.activeElement, target);
}, "Focusable after container size change");
</script>