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+<!doctype html>
+<title>CSS Container Queries Test: Absolute positioned canvas as dynamic size container for focusable child with display</title>
+<link rel="help" href="https://drafts.csswg.org/css-contain-3/#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;
+    position: absolute;
+    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>