<!DOCTYPE html>
<title>CSS Values Test: sign() in keyframes with relative units and font-size change</title>
<link rel="help" href="https://drafts.csswg.org/css-values/#sign-funcs">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<style>
  @keyframes --a {
    from {
      scale: calc(1.5 + sign(1em - 10px));
      rotate: calc(1.5deg + sign(1em - 10px) * 1deg);
      text-size-adjust: calc(1.5% + sign(1em - 10px) * 1%);
      font-weight: calc((1.5 + sign(1em - 10px)) * 100);
    }
    to {
      scale: 1;
      rotate: 1deg;
      text-size-adjust: 1%;
      font-weight: 100;
    }
  }
  #target {
    animation-name: --a;
    animation-duration: 1000s;
    animation-timing-function: steps(2, start);
    width: 100px;
    height: 100px;
    background: teal;
    font-size: 8px;
  }
</style>
<div id="target"></div>
<script>
  test(() => {
    assert_equals(getComputedStyle(target).scale, "0.75");
    assert_equals(getComputedStyle(target).rotate, "0.75deg");
    assert_equals(getComputedStyle(target).textSizeAdjust, "0.75%");
    assert_equals(getComputedStyle(target).fontWeight, "75");
  }, "Initially, the font-size is 8px for #target, so the result is 0.75");

  test(() => {
    target.style.fontSize = "16px";
    assert_equals(getComputedStyle(target).scale, "1.75");
    assert_equals(getComputedStyle(target).rotate, "1.75deg");
    assert_equals(getComputedStyle(target).textSizeAdjust, "1.75%");
    assert_equals(getComputedStyle(target).fontWeight, "175");
  }, "Changing the font-size of #target changes the start point, so the result should be 1.75");
</script>