rem-unit-root-element.html

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This WPT test may be referenced by the following Test IDs:
- /css/css-values/rem-unit-root-element.html - WPT Dashboard Interop Dashboard

<!doctype html>

<title>CSS Values and Units Test: rem units on the root element</title>

<link rel="help" href="https://drafts.csswg.org/css-values/#rem">

<script src="/resources/testharness.js"></script>

<script src="/resources/testharnessreport.js"></script>

<style>

  :root {

    font-size: 50px;

    margin-left: 2rem;

    padding-top: 2rem;

    line-height: 2rem;

</style>

<script>

  let rootStyle = getComputedStyle(document.documentElement);

  test(() => assert_equals(rootStyle.marginLeft, "100px"), "rem based margin.");

  test(() => assert_equals(rootStyle.paddingTop, "100px"), "rem based padding.");

  test(() => assert_equals(rootStyle.lineHeight, "100px"), "rem based line-height.");

  test(() => {

    document.documentElement.style.fontSize = "initial";

    let initialFontSize = parseInt(getComputedStyle(document.documentElement).fontSize);

    document.documentElement.style.fontSize = "3rem";

    assert_equals(getComputedStyle(document.documentElement).fontSize, 3*initialFontSize + "px");

  }, "Check that rem font-size is based on the initial font-size.");

</script>