chromium/third_party/blink/web_tests/fast/forms/color-scheme/checkbox/checkbox-appearance-basic.html

<!DOCTYPE html>
<meta name="color-scheme" content="light dark">
<script src="../../../../resources/run-after-layout-and-paint.js"></script>
<script src="../../resources/common.js"></script>
<body style="background-color: blue">

<!-- no style for reference -->
<input type="checkbox">
<input type="checkbox" checked>
<br>

<!-- border -->
<input type="checkbox" style="border: 3px solid lime;">
<input type="checkbox" style="border-radius: 6px;"> <br>

<!-- background -->
<input type="checkbox" style="background: linear-gradient(to bottom, #dea 0%,#9c7 44%,#494 100%);"> <br>

<!-- shadow -->
<input type="checkbox" style="box-shadow: 4px 4px 10px rgba(255,0,0,0.5), inset 4px 4px 4px rgba(0,255,0,0.5);"> <br>

<!-- size -->
<input type="checkbox" style="width: 8px; height; 8px;">
<input type="checkbox" style="width: 16px; height; 16px;">
<input type="checkbox" style="width: 24px; height; 24px;">
<input type="checkbox" style="width: 26px; height: 20px;">
<input type="checkbox" style="width: 1px; height: 1px;"> <br>

<!-- disabled -->
<input type="checkbox" disabled>
<input type="checkbox" disabled checked> <br>

<!-- indeterminate -->
<input type="checkbox" id="indeterminateCheckbox">
<input type="checkbox" id="indeterminateDisabledCheckbox" disabled> <br>
<input type="checkbox" id="indeterminateCheckbox24px" style="width: 24px; height: 24px;">
<input type="checkbox" id="indeterminateCheckboxZoom4" style="zoom: 4;">
<input type="checkbox" id="indeterminateDisabledCheckboxZoom" style="zoom: 4;" disabled> <br>

<!-- zoom -->
<input type="checkbox" style="zoom: 1.5;">
<input type="checkbox" style="zoom: 2;">
<input type="checkbox" style="zoom: 4;"> <br>

<div style="background-color: white">
  <input type="checkbox" disabled>
  <input type="checkbox" id="indeterminateDisabledWhiteBG" disabled>
  <input type="checkbox" disabled checked>
  <input type="checkbox" checked>
  <input type="checkbox" id="hoverTarget" /> <br>
  <input type="checkbox" id="indeterminateWhiteBG">
  <input type="checkbox" checked style="zoom: 4;">
  <input type="checkbox" checked style="zoom: 4;" disabled>
  <input type="checkbox" id="indeterminateCheckboxZoom4WhiteBG" style="zoom: 4;" disabled>
</div>
<div style="background-color: black">
  <input type="checkbox" disabled>
  <input type="checkbox" id="indeterminateDisabledBlackBG" disabled>
  <input type="checkbox" disabled checked>
  <input type="checkbox" checked> <br>
  <input type="checkbox" id="indeterminateBlackBG">
  <input type="checkbox" checked style="zoom: 4;">
  <input type="checkbox" checked style="zoom: 4;" disabled>
  <input type="checkbox" id="indeterminateCheckboxZoom4BlackBG" style="zoom: 4;" disabled>
</div>

<script>

runAfterLayoutAndPaint(function() {
  indeterminateCheckbox.indeterminate = true;
  indeterminateDisabledCheckbox.indeterminate = true;
  indeterminateCheckbox24px.indeterminate = true;
  indeterminateCheckboxZoom4.indeterminate = true;
  indeterminateDisabledCheckboxZoom.indeterminate = true;
  indeterminateDisabledWhiteBG.indeterminate = true;
  indeterminateDisabledBlackBG.indeterminate = true;
  indeterminateWhiteBG.indeterminate = true;
  indeterminateBlackBG.indeterminate = true;
  indeterminateCheckboxZoom4WhiteBG.indeterminate = true;
  indeterminateCheckboxZoom4BlackBG.indeterminate = true;

  var target = document.getElementById('hoverTarget');
  hoverOverElement(target);
}, true);
</script>
</body>