<!DOCTYPE html>
<link rel="help" href="https://drafts.css-houdini.org/css-properties-values-api-1">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="../resources/utils.js"></script>
<div id="target"></div>
<script>
test(() => {
const customProperty = "--my-length";
CSS.registerProperty({
name: customProperty,
syntax: "<length>",
inherits: false,
initialValue: "100px"
});
target.style.marginLeft = `var(${customProperty})`;
assert_equals(getComputedStyle(target).marginLeft, "100px");
target.style.transition = `${customProperty} 1s -500ms linear`;
target.style.setProperty(customProperty, "200px");
assert_equals(getComputedStyle(target).marginLeft, "150px");
}, "Running a transition a non-inherited CSS variable is reflected on a standard property using that variable as a value");
</script>