<!doctype html> <title>Container Relative Units: in @container prelude (dynamic)</title> <link rel="help" href="https://drafts.csswg.org/css-contain-3/#container-lengths"> <script src="/resources/testharness.js"></script> <script src="/resources/testharnessreport.js"></script> <script src="support/cq-testcommon.js"></script> <style> #outer { container-type: size; width: 40px; height: 40px; } #container { container-type: size; width: 16px; height: 16px; } @container ((width = 16px) and (width = 50cqw)) { #child { --cqw:true; } } </style> <div id=outer> <div id=container> <div id=child>Test</div> </div> </div> <script> setup(() => assert_implements_container_queries()); test(() => { assert_equals(getComputedStyle(child).getPropertyValue('--cqw'), ''); outer.style.width = '32px'; assert_equals(getComputedStyle(child).getPropertyValue('--cqw'), 'true'); }, 'Query with container-relative units are responsive to changes'); </script>