css/css-flexbox/flexbox-overflow-padding-001.html

<!DOCTYPE html>
<html>
  <meta charset="utf-8">
  <title>CSS Flexible Box Layout Test: Test flex container's overflow rect</title>
  <link rel="author" title="Ting-Yu Lin" href="mailto:tlin@mozilla.com">
  <link rel="author" title="Mozilla" href="https://www.mozilla.org/">
  <link rel="help" href="https://drafts.csswg.org/css-overflow-3/#scrollable">
  <link rel="match" href="../reference/ref-filled-green-100px-square.xht">
  <meta name="assert" content="When computing flex container's overflow area, its padding rect is added to flex item's margin-box, not flex item's overflow rect. This test verifies that last part; making sure it's not mistakenly added to the flex container's overflow rect.">

  <style>
  .scroll {
    overflow: auto;
    width: 100px;
    height: 100px;
    background: red;
  }
  .flexContainer {
    display: flex;
    padding: 25px;
    background: green;
  }
  .flexItem {
    flex-shrink: 0;
    width: 30px;
    height: 30px;
    margin: 10px;
  }
  .flexItemOverflow {
    width: 65px;
    height: 65px;
  }
  </style>

  <p>Test passes if there is a filled green square and <strong>no red</strong>.</p>
  <div class="scroll">
    <div class="flexContainer">
      <div class="flexItem">
        <!-- The item's right and bottom overflow edges should exactly touch the
             flex container's right bottom left padding edges. -->
        <div class="flexItemOverflow"></div>
      </div>
    </div>
  </div>
</html>