chromium/third_party/blink/web_tests/animations/custom-properties/resolution-interpolation.html

<!DOCTYPE html>
<meta charset="UTF-8">
<style>
.parent {
  --resolution: 30dppx;
}
.target {
  --resolution: 10dppx;
}
</style>
<body>
<script src="../interpolation/resources/interpolation-test.js"></script>
<script>
CSS.registerProperty({
  name: '--resolution',
  syntax: '<resolution>',
  initialValue: '40dppx',
  inherits: false,
});

assertInterpolation({
  property: '--resolution',
  from: neutralKeyframe,
  to: '20dppx',
}, [
  {at: 0, is: '10dppx'},
  {at: 0.5, is: '15dppx'},
  {at: 1, is: '20dppx'},
  {at: 1.5, is: '25dppx'},
]);

assertInterpolation({
  property: '--resolution',
  from: 'initial',
  to: '20dppx',
}, [
  {at: 0, is: '40dppx'},
  {at: 0.5, is: '30dppx'},
  {at: 1, is: '20dppx'},
  {at: 1.5, is: '10dppx'},
]);

assertInterpolation({
  property: '--resolution',
  from: 'inherit',
  to: '20dppx',
}, [
  {at: 0, is: '30dppx'},
  {at: 0.5, is: '25dppx'},
  {at: 1, is: '20dppx'},
  {at: 1.5, is: '15dppx'},
]);

assertInterpolation({
  property: '--resolution',
  from: 'unset',
  to: '20dppx',
}, [
  {at: 0, is: '40dppx'},
  {at: 0.5, is: '30dppx'},
  {at: 1, is: '20dppx'},
  {at: 1.5, is: '10dppx'},
]);

assertInterpolation({
  property: '--resolution',
  from: '10dpi',
  to: '20dpcm',
}, [
  {at: 0, is: '0.104167dppx'},
  {at: 0.5, is: '0.316667dppx'},
  {at: 1, is: '0.529167dppx'},
  {at: 1.5, is: '0.741667dppx'},
]);

assertInterpolation({
  property: '--resolution',
  from: '200dpi',
  to: '90dppx',
}, [
  {at: 0, is: '2.08333dppx'},
  {at: 0.5, is: '46.0417dppx'},
  {at: 1, is: '90dppx'},
  {at: 1.5, is: '133.958dppx'},
]);
</script>
</body>