chromium/third_party/blink/web_tests/wpt_internal/printing/page-fitting-001-print-ref.html

<!DOCTYPE html>
<script>
  if (window.testRunner) {
    testRunner.setShouldCenterAndShrinkToFitPaper(false);
  }
</script>
<style>
  @page {
    size: 400px 300px;
    margin: 0;
  }
  body {
    margin: 0;
  }
  .page {
    display: flex;
    overflow: clip;
    height: 100vh;
  }
  .page > div {
    margin: auto;
    background: yellow;
  }
</style>
<div class="page">
  <div style="width:160px; height:160px;">
    Small, centered on "paper".
  </div>
</div>
<div class="page">
  <div style="width:360px; height:260px;">
    The second page has the default size.
  </div>
</div>
</div>
<div class="page">
  <!-- Margins are also downscaled. -->
  <div style="width:280px; height:280px;">
    <div style="transform-origin:top left; scale:0.5; width:200%;">
      The third page is large, and scaled down and centered on "paper".
    </div>
  </div>
</div>