<!DOCTYPE html>
<link rel="help" href="https://github.com/w3c/csswg-drafts/issues/7639">
<style>
.target {
  display: flex;
  inline-size: 200px;
  position: relative;
  line-height: 0;
  margin: 40px;
  padding: 10px;
  writing-mode: vertical-lr;
}
.target > div {
  background: hotpink;
  font-size: 20px;
}
.multicol {
  columns: 3;
  column-fill: auto;
  padding: 10px;
  border: solid 10px;
}
.multicol > div {
  break-inside: avoid;
  break-before: column;
  break-after: column;
}
span {
  display: inline-block;
  width: 1em;
  height: 1em;
  outline: solid cyan 3px;
  outline-offset: -3px;
}
</style>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/resources/check-layout-th.js"></script>
<body onload="checkLayout('.target > *')">

<!-- Three columns, largest in the middle. -->
<div class="target" style="align-items: first baseline;">
  <div data-offset-x="25"><span></span></div>
  <div class="multicol" data-offset-x="10">
    <div style="font-size: 10px;">
      <span></span><br><span></span><br><span></span>
    </div>
    <div style="font-size: 30px;">
      <span></span><br><span></span><br><span></span>
    </div>
    <div style="font-size: 20px;">
      <span></span><br><span></span><br><span></span>
    </div>
  </div>
</div>

<div class="target" style="align-items: last baseline;">
  <div data-offset-x="95"><span></span></div>
  <div class="multicol" data-offset-x="10">
    <div style="font-size: 10px;">
      <span></span><br><span></span><br><span></span>
    </div>
    <div style="font-size: 30px;">
      <span></span><br><span></span><br><span></span>
    </div>
    <div style="font-size: 20px;">
      <span></span><br><span></span><br><span></span>
    </div>
  </div>
</div>

<!-- Start spanning element. -->
<div class="target" style="align-items: first baseline;">
  <div data-offset-x="30"><span></span></div>
  <div class="multicol" data-offset-x="10">
    <div style="column-span: all; background: orange;">
      <span></span><br><span></span>
    </div>
    <div style="font-size: 10px;">
      <span></span><br><span></span><br><span></span>
    </div>
    <div style="font-size: 30px;">
      <span></span><br><span></span><br><span></span>
    </div>
    <div style="font-size: 20px;">
      <span></span><br><span></span><br><span></span>
    </div>
  </div>
</div>

<div class="target" style="align-items: last baseline;">
  <div data-offset-x="135"><span></span></div>
  <div class="multicol" data-offset-x="10">
    <div style="column-span: all; background: orange;">
      <span></span><br><span></span>
    </div>
    <div style="font-size: 10px;">
      <span></span><br><span></span><br><span></span>
    </div>
    <div style="font-size: 30px;">
      <span></span><br><span></span><br><span></span>
    </div>
    <div style="font-size: 20px;">
      <span></span><br><span></span><br><span></span>
    </div>
  </div>
</div>

<!-- End spanning element. -->
<div class="target" style="align-items: first baseline;">
  <div data-offset-x="25"><span></span></div>
  <div class="multicol" data-offset-x="10">
    <div style="font-size: 10px;">
      <span></span><br><span></span><br><span></span>
    </div>
    <div style="font-size: 30px;">
      <span></span><br><span></span><br><span></span>
    </div>
    <div style="font-size: 20px;">
      <span></span><br><span></span><br><span></span>
    </div>
    <div style="column-span: all; background: orange;">
      <span></span><br><span></span>
    </div>
  </div>
</div>

<div class="target" style="align-items: last baseline;">
  <div data-offset-x="140"><span></span></div>
  <div class="multicol" data-offset-x="10">
    <div style="font-size: 10px;">
      <span></span><br><span></span><br><span></span>
    </div>
    <div style="font-size: 30px;">
      <span></span><br><span></span><br><span></span>
    </div>
    <div style="font-size: 20px;">
      <span></span><br><span></span><br><span></span>
    </div>
    <div style="column-span: all; background: orange;">
      <span></span><br><span></span>
    </div>
  </div>
</div>
